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Facts about processes, 
pigments and vehicles 



Arthur Pillans Laurie 






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PKOCESSES, PIGMENTS, AND 
VEHICLES 



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GRINDING COLOURS ON THE MULLER :• 

(A Half-tone Process Block from a Photograph) 



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FACTS 



ABOUT 



PEOCESSES, PIGMENTS 
AND VEHICLES 

A MANUAL FOR ART STUDENTS 



A. P. LAURIE, MA., B.Sc. 

LECTURER ON CHEMISTRY, ST. MARK'S H08P1TAL \ LATE FELLOW 



KINO S COLLEGE, CAMBRIDGE 



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ILontion 

MACMILLAN AND CO. 

AND NEW YORK 
1895 

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PUBLIC LIBRARY 

445347 A 

ASrOB, LENOX AND 

TILDE* FOUNDATIONS 

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PREFACE 

This book is merely intended to form a simple and 
elementary introduction to a difficult and complex subject, 
which involves a considerable amount of scientific know- 
ledge for its complete mastery. Those wishing to pursue 
the subject further must consult more advanced books. 

The aims and scope of the book are fully explained 

in the Introduction, so that there is no need to say 

anything here beyond acknowledging how enormously 

I am indebted to Professor Church and his book on 

Paints and Painting for the information contained in the 

following pages. 

•j I must also thank him here for the personal assistance 

. he has always given me in my study of this subject ; and 

7 must also thank Mr. Farmer, of the Regent Street Poly- 

* technic, for his invaluable assistance while I was preparing 

- the chapter on Process. I have tried to give a fair judg- 



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viii PROCESSES, PIGMENTS, AND VEHICLES 

ment of half-tone work ; but there is such a marked differ- 
ence between process prints as exhibited by process-block 
makers and as reproduced in books and magazines, that it 
is difficult to judge the process fairly. The process-block 
makers blame the printers, and this is probably the correct 
explanation. Captain Abney has proposed and is testing 
at South Kensington a method of protecting pictures by- 
absorbing the more chemically -active rays of the light 
entering the Gallery, which should prove of great use. It 
does not, however, do away with the necessity of the 

precautions described in this book. 

A. P. Laurie. 



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CONTENTS 



INTRODUCTION 



PAGE 

1 



PART I 



AN EXPERIMENTAL COURSE ON PIGMENTS AND VEHICLES 



CHAP. 

1. how to grind a pigment in water, oll, or other 

Medium 

2. On the Testing of the Durability of Pigments by 

EXPOSING THEM TO LlGHT AND AlR 

3. The Yellow Ochres and Raw Sienna 

4. The Red Ochres and Terre Verte 

5. The Umbers .... 

6. The Bitumens and Bituminous Earths 



7. White Lead (Flake White), Barytes, 

Lead Sulphate 

8. Some Important Ahtificial Yellows 

9. Some Important Artificial Reds 

10. Some Important Artificial Blues 

11. Some Important Artificial Greens 



Zinc White. 



13 

16 
22 
27 
33 
36 

40 
50 
54 
57 
60 



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x PROCESSES, PIGMENTS, AND VEHICLES 

CHAP. PAGE 

12. Some Important Artificial Blacks . . .63 

13. Oils ....... 65 

14. Varnishes ....... 70 



PART II 

NOTES ON ' PROCESS,' AND ON TEMPERA, FRESCO, WATER- 
COLOUR, AND OIL-PAINTING 



15. Drawing for Process 

16. Tempera Painting .... 

17. Fresco Painting .... 

18. Water-Colour Painting . 

19. Oil-Painting .... 

Glossary of Pigments .... 

Index ...... 

List of Apparatus and Chemicals required 



81 

99 

106 

111 

114 

119 
125 
129 



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INTRODUCTION 

The object of this book is to give art students a practical 
acquaintance with the preparation and properties of 
pigments and vehicles, and to familiarise them with those 
more important facts which are of direct application to 
painting. Though it would be absurd to expect artists at 
the present time to prepare their own pigments, oils, 
varnishes, and canvases, yet it is necessary for the right 
understanding of their work that they should know the 
nature of these substances and something of their modes 
of preparation. He is a poor workman who knows nothing 
of his tools. 

It is, however, difficult for them to understand scientific 
treatises on pigments, and there is little learnt by mere 
reading or listening to lectures. Real knowledge is to be 
obtained only through the actual seeing and handling of 
things. For this reason I propose to depart in this book 
from the usual method, and to put before the student a 
series of simple observations and experiments by which 
he may become practically acquainted with the nature 
and properties of pigments. By a small expenditure in 
cheap and simple apparatus, art schools will be enabled 
to put their students through an experimental course which 
will both interest them and impart a genuine knowledge 



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2 PROCESSES, PIGMENTS, AND VEHICLES 

of the subject, while any further information they may 
require, can be readily obtained by consulting more com- 
prehensive text-books, which will be readily understood 
after this preliminary training. In pursuance of this 
design the book has been divided into two parts. 

The first part consists of a series of simple practical 
lessons on the properties and preparation of pigments, 
oils, and varnishes. The experiments should be performed 
by the student himself. The second part contains a brief 
chapter on the methods of process reproduction, and some 
notes on painting in tempera, water-colours, frescoes of 
different kinds, and oil. 

Then follows in the Appendix an attempt at a complete 
list of pigments, with some information about their 
durability in different media. 

Some apology and explanation is perhaps due for the 
chapter on ' Process.' While reproduction by photographic 
methods is being vehemently denounced by some, it is at 
the same time supplying a livelihood to many, and I am 
disposed to think that * process work' has its legitimate 
place, among other methods of reproducing the work of 
the artist. While it does not replace in any way the 
good woodcut, or good copper or steel engraving or 
etching, it is a useful method for reproducing line work 
of a bold and simple character, and reproducing it 
accurately. Beyond this I doubt its value or permanent 
position as a method of reproduction. All half-tone work 
seems to me of doubtful value, and may be expected in 
time to disappear. But I hope that my chapter on 
process work may not be entirely useless from an artistic 
point of view; and that by pointing out some of the 
deficiencies and limitations of process work and its purely 
mechanical methods for the imitation of certain effects, it 



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INTRODUCTION 3 

may help both artists and the public to realise its legiti- 
mate and humble place among methods of reproduction, 
and so may check the tendency to use merely mechanical 
dodges that deceive the untrained eye into the belief 
that it is gazing on the subtle work of the hand of the 
artist. 

The production of a durable painting, whether on the 
wall of a building or on a panel or a piece of canvas, 
whether in fresco or in oil, in water-colour or in tempera, 
is a difficult problem; and because it is difficult, it is 
one to which the artist should devote considerable 
thought. For it is his duty not only to turn out a 
work of art, but also to turn out a good job, in which 
good materials have been used, and the best possible 
devices adopted to insure the permanency of the work. 
He should no more use fugitive paints than the carpenter 
should use unseasoned wood, and he should take at 
least as much trouble to prevent his work from fading and 
"falling to pieces as the house -painter or coach -painter 
would do. 

Unfortunately, the difficulties are many, and there is 
no one method or process which can be advised as per- 
fect, each having its own defects and dangers. Then the 
multiplicity of new pigments discovered every day further 
enhances the difficulties and places ' new pitfalls before 
the unwary artist. And though modern chemistry, re- 
penting somewhat of her evil deeds in inventing innumer- 
able fugitive pigments, has lately turned her attention 
to the problem of how to produce durable pictures, yet 
at the end of the researches made by Professor Church 
and others, I doubt if we can claim to know so 
much about the subject as a fifteenth -century painter. 
The reason for this is not far to seek. The old 'prentice 



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4 PROCESSES, PIGMENTS, AND VEHICLES 

method of training artists resulted in the accumulation 
of invaluable traditions, traditions all the more useful, 
as in those days the painter prepared his own materials, 
or, to speak more correctly, employed his apprentice to 
do so. The apprentice was consequently familiar with 
every material and every process used in the production 
of a picture, and would himself observe the success 
or failure of the different processes and preparations on 
his master's picture years afterwards, and detect what 
was good and what was bad in the methods he had then 
learned. Then the number of pigments and of media 
was limited, and their properties, advantages, and defects 
were studied with slowly-accumulating experience, which 
was not disturbed by the discovery of new pigments or 
the introduction of old pigments under new fancy names. 
From the moment the colourman was separated from the 
artist, and the experimental chemist from both, all 
inevitably became confusion. 

But these are not the only difficulties : not only has 
the artist lost the valuable training of apprenticeship, 
lasting, according to Cennino Cennini, ten years before 
the apprentice began to paint a picture, but he has 
further been overwhelmed by the rapid growth of 
modern chemistry, which has resulted in the production of 
large numbers of new pigments, and the development of a 
marvellous skill in imitation and adulteration. Even this 
does not complete the story ; there is another factor, and 
that is the change that has come on the methods of 
painting themselves. It is useless to expect from the 
artist of to-day, painting rapidly, trying to grasp subtle 
effects of atmosphere and delicate evanescent shades and 
tones of colour, the patient building up of a picture from 
the beginning, with the use of varying media according 



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INTRODUCTION 5 

to the pigment on the brush, and other devices to insure 
permanent work. Finally, a new enemy has arisen in 
the shape of coal, which, pouring out from every chimney 
powerful acids, and tarry particles which can eat into the 
oils and varnish, and sulphur compounds which darken 
the white lead and other lead pigments, puts the finishing 
touch on the troubles of the artist who wishes to produce 
a permanent piece of work. 

There is, however, another side to this gloomy picture, 
and modern chemistry has not been wholly inimical 
to the artist. The older painters had to struggle with 
the difficulties of a limited palette containing notoriously 
fugitive pigments, and had to resort to many devices to 
protect them from change. The discoveries of modern 
chemistry, while adding enormously to the list of fugitive 
pigments, has also added to the list of permanent ones, 
and consequently has put at the command of the painter 
of to-day an ample palette of pigments which may be 
trusted to resist change, and would have excited the 
envy of Van Eycke. Added to this, the systematic and 
useful experimental work carried on by Professor Church, 
Professor Kussell, Captain Abney and others, is rapidly 
resulting in more and more exact information as to the 
properties and behaviour of vehicles and pigments, so 
that the artist of to-day who chooses to avail himself of 
the results of all this work, may hope to produce fairly 
durable pictures. The great point is the careful selection 
of the palette. There is no difficulty in obtaining all 
the pigments necessary, and yet avoiding fugitive pigments, 
or pigments which act injuriously on each other. But in 
selecting the palette it must be remembered that each 
process requires a different selection, and that the list of 
pigments suitable for oil paintings is not suitable for 



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6 PROCESSES, PIGMENTS, AND VEHICLES 

water-colour or fresco. One of the principal reasons 
why so many modern efforts at fresco have come to 
grief, is that those painting in fresco have not realised 
the rigid limitations of the art caused by the fact that few 
pigments can withstand the action of lime. Cennino 
Gennini writing in the fifteenth century mentions only 
five pigments which can be safely used in fresco, but this 
number can now be increased by the inclusion of certain 
modern pigments which may safely be trusted. 

Besides the selection of pigments there are other 
matters of much importance which the artist must bear 
in mind. For instance, in using oil as a medium, the 
artist obtains the advantage to a certain extent of pro- 
tecting his pigments from external influences ; but, on the 
other hand, he has the disadvantage of using a medium 
which is apt to yellow and to crack. Yellowing can be 
cured by placing the picture in a window, and exposing 
it to bright light, while avoiding the direct play of the 
sun's rays upon it, and this process can do no harm, if jwr- 
manent pigments have been used. 

Cracking is a more serious question, and one difficult 
of solution. It is probably in most cases due to too 
hasty painting, and to the use of rapid dryers, but in 
many cases it happens in a most capricious manner, 
which is difficult to account for. Too hasty varnishing 
is also recognised as a serious evil, causing the picture 
to crack, but after all these admissions there is much 
here which has never been explained. 

In water-colour painting, again, the pigments are left 
on the paper with no protection, and consequently a limited 
palette is here necessary if change is to be avoided, and care 
must also be taken to protect the picture from mechanical 
rubbing of the surface, which is sure to remove some of 



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INTRODUCTION 7 

the colour. The question of the preservation of valuable 
water-colours is one which has excited considerable con- 
troversy, and does not yet seem to be decided, but there 
are two things to be borne in mind. In the first place, the 
pigments used by the older painters in water-colours were 
not selected with any scientific skill, and consequently 
contain fugitive pigments. In the second place, it has 
been proved by many experiments that these fugitive 
pigments are not seriously attacked by air and moisture 
if kept in the dark, but are rapidly attacked in sunlight, 
and more slowly in ordinary diffused daylight. Valuable 
water-colours should therefore be kept in the dark, and 
only exposed to light when being actually examined. 
They should also be kept dry, and free from dust and 
dirt. Probably the best plan for water-colours in public 
galleries would be to fit them with spring blinds, working 
the reverse way to those usually found in private carriages ; 
the spring or attached weights keeping the blind down, 
when not pulled up by hand. An arrangement could be 
added for fixing the blind up if necessary when a picture 
was being copied, but this should be done by a key in the 
possession of an official. In this way the protection of the 
water-colours from light would be insured. 

For the preservation of valuable oil pictures it is advis- 
able, after careful cleaning of the surface and drying, to 
cover them with a thin coating of mastic varnish. This 
forms a protective coating which can be easily removed 
and renewed at any time without injuring the picture 
beneath, thus keeping it clean and free from the attacks 
of acids and tarry matters derived from coal fires and gas 
jets. 

A picture gallery should be neither too dry nor too 
moist, and should be kept, if possible, at an equable 

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8 PROCESSES, PIGMENTS, AND VEHICLES 

temperature. Many a picture has been doubtless de- 
stroyed by the absorption of moisture by the canvas, and 
then by the freezing of the moisture during the night and 
thawing during the day, cracking off the ground. 

On the whole it is advisable to protect the backs of 
canvases. This can be done in various ways, which will 
be described later on. 

Panels can always be protected by a good coating of 
oil paint on the back and edges. 

Though it is necessary to include a description of fresco 
painting in a book of this kind, it should, I think, be 
discarded in this country, especially in large towns and 
factory districts, for spirit fresco. It is so very difficult to 
clean a real fresco successfully. Professor Church has 
recently, however, accomplished this difficult feat by clean- 
ing the fresco by Watts in the Inns of Court. This he 
managed by carefully going over the surface with spirits 
of wine and cotton wool. He then, after cleaning, sprayed 
the whole with his spirit fresco medium, so as to protect 
it in future from change. A similar process might be 
adopted for the preservation of other frescoes which are 
suffering from the exposure of their unprotected surface 
to damp and dirt and injurious gases. 

Much more attention should be given to the condition 
of the atmosphere in our public galleries, little or nothing 
being now done to protect the pictures from change. 
There is no reason why the air should not be carefully 
filtered from dirt and smoke particles, injurious substances 
such as sulphuric and sulphurous acid and sulphuretted 
hydrogen removed, and the temperature and amount of 
moisture exactly regulated. It is also worthy of trial 
whether the life of water-colours might not be prolonged 
by keeping them in cases, in which the air was dried 



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INTRODUCTION 9 

artificially by passing it over calcium chloride or quick- 
lime. The expense of such precautions is trifling when 
compared with the priceless value of the collections in the 
National Gallery and South Kensington. But we have 
more to do here with the production of modern pictures 
than the preservation of old ones, and I shall therefore 
now pass on to treat of the properties of a selected number 
of pigments and vehicles. 



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PART I 

AN EXPERIMENTAL COURSE ON PIGMENTS 
AND VEHICLES 



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CHAPTER I 

HOW TO GRIND A PIGMENT IN WATER, OIL, OR OTHER 
MEDIUM 

For this purpose a muller and slab must be obtained. 
These are made of various sizes, but a muller 2£ inches 
in diameter and a stone or glass slab 9 inches each way are 
all that is needed. 

The colour mixed with water or oil, as the case may 
be, is ground upon the stone with the muller. 

The muller is moved over the stone with a circular 
motion, or backwards and forwards, and the movement is 
so regulated as to keep the colour in the middle and not 
let it run towards the edges of the stone. Skill is soon 
obtained by a little practice. 

Of course the pigment collects round the muller, and 
must be scraped off with a spatula and placed in the 
middle of the stone again. 

If any quantity of colour is to be ground, it is best to 
use two spatulas, one for placing the unground pigment on 
the stone, the other for scraping up the ground colour and 
putting it on one side. Before beginning, mix the pigment 
with the medium into a fairly stiff paste, and then lift up 
a little portion (for a muller of the size described, a portion 



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14 PROCESSES, PIGMENTS, AND VEHICLES 

about the size of a filbert), place it in the middle of the 
slab, and begin grinding with the circular action already 
described. When the colour is sufficiently fine, scrape it 
off the stone slab with the clean spatula. This is best 
done by running the spatula, lying nearly flat, across the 
stone, then turning the edge free from colour downwards, 
and giving it a tap on the stone so as to cause the colour 
to slide from the edge towards the middle of the blade. 
Then give another scrape to the muller, and so on till 
all the colour has been removed. If the muller is not 
overloaded with colour, no difficulty will be found in 
grinding the colour fine. 

Whether the colour is sufficiently fine can be judged 
by rubbing a little out with the finger on the blade of the 
spatula or on a piece of glass, or porcelain glass, or a 
common white plate. When fine it should rub out 
smoothly and not show any separate coarse particles. The 
degree of fineness, however, can best be judged by com- 
paring it with the same pigment as supplied by the artist's 
colourman. 

The frontispiece shows colour being ground on a 
large slab with a big muller, the heap of colour ready 
for use lying in one corner, and the two spatulas lying in 
position. The drawing also shows how to hold a large 
muller. In the case of a smaller muller only one hand is 
used. 

If the slab tends to shift about during the grinding, it 
is easily fixed in position by means of two pieces of wood 
screwed down to the table on each side of the slab. 

Mullers and slabs are made of glass, marble, granite, 
etc. 

I prefer a muller made of some hard pebble, and a 
marble slab, but the other materials are quite satisfactory. 



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PIGMENTS 15 

Experiment 1 

Practise grinding a little yellow ochre in oil, comparing 
the result you obtain with a commercial sample. 

You will obtain the same degree of fineness with ease, 
but not the same consistence. Your pigment will be thin and 
treacly, not stiff &nd crisp. 

The secret of this stiffness will be explained later on. 
It is of no importance to us just now. 

Experiment 2 

Clean the muller with some turpentine or paraffin and 
an old rag or handful of waste, and practise grinding some 
yellow ochre in water. 

This is more difficult, as the muller is apt to stick to the 
stone, and some practice is needed. 

Clean the muller and slab with a little soap and water. 

Having now learnt how to grind small quantities of 
pigments, we shall proceed next to the question of how to 
test their durability. 



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CHAPTEE II 

ON THE TESTING OF THE DURABILITY OF PIGMENTS 
BY EXPOSING THEM TO LIGHT AND AIR 

The durability of pigments depends on many conditions. 
They may be altered by contact with other pigments or 
by contact with impure paper, or badly-prepared grounds, 
or injurious media ; they may be affected by special gases 
present in the atmosphere. These different causes of 
change we shall examine in due time. But in the majority 
of cases pigments yield simply to the action of light, air, 
and moisture. This gives us a very convenient method of 
applying a simple test to decide whether a pigment is 
durable or not. 

The action of air and moisture is enormously in- 
creased by exposing a pigment to a strong light. 

So much so that Captain Abney has calculated that two 
years' exposure to the direct light from out of doors is 
equivalent to four hundred years' exposure to the light of 
a picture gallery. Some realisation of the enormous 
difference between outdoor and indoor light may be 
obtained by noticing that a room looked into from the 
outside seems to be quite dark. By therefore exposing 



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DURABILITY OF PIGMENTS IN LIGHT 17 

pigments to direct daylight, we can in a few months 
classify them, and separate those that are fugitive. 

I shall begin by describing how water-colour washes 
may be examined. This may be done by starting from 
the pigment as supplied in water by the artist's colourman, 
but it is better to prepare from the dry pigment, grinding 
it with a muller in water. 

Prepare some colour by grinding it on the muller with 
water, removing the paste to a little wide-mouthed bottle, 
and then adding a few drops of gum arable solution. 
Common gum should, not be used, but some pure gum 
arabic should be bought at a chemist's, and then dissolved 
in warm water. This is best done by putting the gum 
arabic and the water in a bottle and then placing the 
bottle in a saucepan of hot water which is kept nearly 
boiling beside the fire. If from time to time the bottle 
is shaken up the gum arabic will dissolve without diffi- 
culty. 

Next dilute the pigment in the little bottle with 
sufficient water, and dip into it a large soft brush, and 
paint out a thin light wash of colour on a strip of 
Whatman's paper about six inches long by three inches 
broad. 

Cork up the bottle containing the colour and allow the 
wash of colour on the paper to dry completely. 

When dry, thoroughly stir up the colour in the bottle 
and lightly lay on a second wash of colour over the first, 
using all the paper except a strip about one inch broad at 
the bottom. Again allow the paper to dry, and again lay 
on a wash of colour over all the paper except a strip at 
the bottom about two inches broad. 

This process is repeated until five washes have been 
laid on (this is a convenient number), the top of the paper 

c 



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1 8 PROCESSES, PIGMENTS, AND VEHICLES 

being coated with five washes, the next portion with four, 
the next with three, and the last strip at the bottom with 
only one. 

We have thus prepared a graduated scale for measuring 



WASHES OP CRIMSON LAKE 

depths of colour, and if we have been careful to mix the 
pigment thoroughly with the water each time, and to 
keep the bottle corked between whiles, each wash of 
colour will roughly correspond in strength to the others. 
The amount of dilution of the pigment required will be 
proved by one or two trials. The washes of colour 



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DURABILITY OF PIGMENTS IN LIGHT 19 

should be strong enough to show clearly the difference 
between the first and second wash, and at the same time 
they should not be so strong that the distinction between 
the fourth and fifth wash is not clearly marked. Having 
thus prepared the paper of graduated tints, secure a 
cheap picture frame with glass in front and easily-remov- 
able back, and cutting off half of the top of the paper 
coated with five washes, fix it into the inside of the glass 
with some bits of stamp paper at the corners, and replacing 
the back, hang the picture frame up in a window, so that 
it shall get all the light going. 

A very large number of tests can be made in this way 
on a single sheet of glass, each piece of paper being about 
one inch each way, and so occupying very little space. 

The piece of paper should be numbered, and the 
number should be entered in a book, with a statement as 
to the nature of the pigment and the date of exposure, 
and space left for further entries. The graduated washes 
of colour should be kept in a drawer, dry and free from 
light. 

From time to time the piece of paper pasted on the 
glass is compared with the graduated washes, and any 
change of tint with the date entered in the book, and the 
amount of fading measured by comparison with the 
graduated washes of colour. 

Furthermore, it is as well to expose along with the 
pigment some well-known fugitive pigment like crimson 
lake, so as to compare the results obtained. 

In fact, the student had best prepare a large sheet of 
paper with crimson lake in five washes, and keep it in the 
dark, and from time to time cut off small portions and 
expose it beside the pigment he is testing. In this way 
he will get a single standard of comparison. 



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20 PROCESSES, PIGMENTS, AND VEHICLES 

Experiment 3 

Prepare as described five washes of crimson lake and of 
a strong madder lake, and expose a portion of each side by 
side, and note the changes in each from time to time. 

Durability of Pigments in Oil 

The method just described is of the first importance, 
but it is also as well to test how far pigments are per- 
manent in oil, as well as in water. Unfortunately, we 
cannot obtain in this case a numerical measure of fading, 
but we can, nevertheless, collect much useful information. 

For this purpose get a box for holding ' quarter plates ' 
from a shop which supplies photographic requisites, and 
obtain from a glazier's a set of glass plates, double the 
length of ' quarter plates.' 

Grind the colour to be tested in oil, and rub out a patch 
of the colour as evenly as possible in the middle of the 
plate. The oil used should be a quick drying pale boiled 
oil, as, if raw oil is used, the pigment will take a long time 
to dry. 

Next put the plate away in some convenient corner to 
dry, in the dark, and free from dust. When dry cut the 
plate neatly in half, right through the patch of colour. 
As this requires some special skill, it is best done by a 
glazier. Place a label with a number referring to the 
entry in your note-book on each plate, and put one half 
away in the quarter-plate box, and expose the other half 
to direct daylight. A very convenient arrangement for 
doing this is a wooden frame. It contains grooves for the 
plates to slide in, and along one side the groove is cut 
right through the wood so as to make a slit by which the 



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DURABILITY OF PIGMENTS IN OIL 



21 



plate to be tested can be slid into the frame. The frame 
can then be hung up outside or in a window close to the 
glass. From time to time compare the two halves of 




FRAME FOR EXPOSING OIL COLOURS 



glass by laying them together as they were before cutting, 
and judge how far the pigment is fading, entering the 
result, with the date, in your note-book. 



Experiment 4 

Compare in this way the fading of crimson lake in oil 
with the fading of crimson lake in water. 

We have now learnt how to test the durability of 
pigments, and in future when we examine the properties 
of a pigment, we shall expose a portion of it to light after 
the manner described above, so as to collect information as 
to the durability of pigments. 

We shall now pass on to the consideration of the 
properties of the earths. 



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CHAPTER III 

THE YELLOW OCHRES AND RAW SIENNA 

The large and important group of pigments included under 
these names are of great value to the artist. They have 
this in common, that they are natural pigments which owe 
their colour to the presence of iron in combination, and 
having been produced by the slow action of moisture 
and other agents are remarkably durable. 

The ochres are Yellow Ochre, Golden Ochre, 
Oxford Ochre, Roman Ochre, and closely allied to these 
raw sienna. 

These ochres are obtained by mining in various parts of 
the world, in Oxfordshire, Derbyshire, Wales, Cornwall, 
and parts of France and Italy. 

After removal from the mine the crude ochre is either 
mixed with or ground with water. The coarser particles 
are then allowed to settle, and the finer particles, which 
are still floating in the water, are drawn off into another 
tank and some of the ochre allowed to subside. The 
water is then drawn off, and the still finer particles allowed 
to subside in a second tank, and so on, usually four tanks 
being used in succession. 

In this way the ochre, which is a yellow clay and easily 



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OCHRES 23 

suspended in water, is separated from the stones and sand 
mixed with it. 

The process can easily be illustrated with a little 
garden soil. 

Experiment 5 

Dry some garden soil and sift it through muslin to 
remove the stones, roots, etc., then grind in a mortar 
for a few seconds with some water, pour the water care- 
fully off into another vessel, again grind the soil with 
water, pour off the water, and repeat the operation until 
the water comes off clear and free from mud. 

You will now find in the bottom of the mortar coarse 
sand, while if you allow the mud in the second vessel to 
subside for some time and then pour off the water, you 
will find a fine sticky mud. 

When the ochres have thus been separated from sand 
and other impurities, they are dried at a gentle heat, and 
are ready to be ground in oil or in any other painting 
medium. 

Ochres are yellow clays, and in a sense could be 
obtained almost everywhere, but it is only in certain locali- 
ties that they are found sufficiently fine in colour to be 
worth preparing for use by painters. 

Though we have seen how ochres are prepared, we 
have not yet decided to what the colour of the ochre is 
due, and as this is a matter of considerable importance, we 
must settle it by means of a simple chemical test. 

Experiment 6 

Take a little piece of thin iron wire and boil it up in a 
test-tube for a few minutes in hydrochloric acid with the 

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24 PROCESSES, PIGMENTS, AND VEHICLES 

addition of a crystal of chlorate of potash. Most, if not all, of 
the iron will dissolve. Now dilute the yellow solution with 
water, and add a few drops of a solution of potassium ferro- 
cyanide. A deep blue precipitate is at once formed in the 
solution. This precipitate we shall have to mention again 
later on, but at present we can use it as a simple means 
of detecting the presence of iron in a liquid. 

Experiment 7 

Now boil up a little dry yellow ochre in the same way 
with hydrochloric acid and chlorate of potash and add 
potassium ferrocyanide. We shall at once obtain the 
same deep blue precipitate, thus showing the presence 
of iron in the ochre. It is to the presence of certain 
compounds of iron that the yellow colour of the ochre is 
due. 

Having then settled this question, let us next compare 
different ochres together both in powder and in oil. 

Experiment 8 

Grind a little pinch of each ochre you wish to examine 
on the muller with a few drops of oil, scrape it up with a 
spatula and rub it out with the finger on a white plate. 
On comparing these different ochres together you will 
notice that they differ both in colour and transparency; 
the pale yellows being somewhat opaque, while the browner 
shades approach nearer to raw sienna in character. Not 
only so, but if the ochres sold by different colour-makers 
are compared, they will be found to vary considerably, the 
yellow ochres and the golden ochres of one firm differing 
from those of another. The reason of this is not far to 



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RAW SIENNA 25 

seek. Enormous quantities of yellow ochre are mined 
every year and brought into the market for house-painting 
purposes. But every now and then a 'pocket/ as it is 
called, of especially fine ochre is found, and is offered to 
the artists' colourmen. Each find may be secured by one 
firm or another and may last them for many years, but 
no two pockets will produce two ochres exactly alike. 

Eaw Sienna 

This is an ochre containing a little ' manganese ' (a sub- 
stance which we shall consider later on) as well as iron. 
It is found in the neighbourhood of Kome, and forms the 
last of the series of transparent brown ochres. 

Ochres are seldom adulterated, but Professor Church 
has occasionally found them brightened by the addition of 
a yellow lake, and I have found them brightened in the 
same way by the addition of chrome yellow. Both these 
practices are very objectionable. The addition of yellow 
lake is objectionable because the lake fades quickly, the 
addition of chrome yellow, because chrome yellow is so 
easily darkened by sulphur compounds. To prove this, 

Experiment 9 

Mix a little chrome yellow and yellow ochre together, 
and grind them in oil and rub out the colour on a white 
plate. 

Now rub out on the same plate a pure yellow ochre 
ground in oil but not mixed with chrome. 

Next pour into a small vessel a little sulphide of 
ammonium, and add to it some hydrochloric acid. Some 
sulphuretted hydrogen gas will be given off, and may be 
recognised by the smell of rotten eggs. 



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26 PROCESSES, PIGMENTS, AND VEHICLES 

Cover up the mouth of the vessel with the plate con- 
taining the patch of yellow ochre and the patch of yellow- 
ochre and chrome mixed, leav- 
ing it on the vessel for a few 
seconds so as to expose the 
pigments to the gas. On 
examining each patch, the 
yellow ochre will be found 
unchanged, while the chrome 
yellow will have turned dark 
brown. 

BKAKER AND GLASS PLATB m , . , , , 

This experiment shows how 
injurious the presence of chrome yellow may be. Its 
presence may be recognised in the way just described or 
in the following manner : — 

Experiment 10 

Boil the dry mixture of chrome yellow and yellow 
ochre with a little sulphuric acid and spirits of vine. If any 
chrome is present, the spirits of wine will turn dark green. 

Yellow ochres, when pure, are quite permanent, 
and do not affect other pigments. 

Experiment 11 

Expose a wash of yellow ochre as directed in Chapter II. 
to light. 



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CHAPTEE IV 

THE RED OCHRES AND TERRE VERTE 

Having now considered the yellow ochres, we pass 
naturally to the consideration of the red ochres, which are 
derived in many cases from them. These are known as — 

Red Ochre, Brown Ochre, Red Oxide, Venetian 
Red, Light Red, Indian Red, Purple Ochre, Purple 
Oxide, Mars Red, Mars Purple. Burnt Sienna, 
Rouge, etc. 

There are two common ways of preparing these pigments, 
and the first of these is gently roasting a yellow ochpe. 

Experiment 12 

Gently roast a little yellow ochre on a sheet of iron 
over a Bunsen burner, or over the fire, turning it over and 
over all the while. It will rapidly turn of a bright red 
colour, and if the heating is continued the red will become 
of a more purple shade. 

Grind a little of this pigment in oil and compare its 
colour with commercial red ochres. 

Paint out a wash of this pigment in water and expose 
to light. 



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28 PROCESSES, PIGMENTS, AND VEHICLES 

In this simple way can red ochre be obtained, and 
by a longer and stronger heat purple shades can also be 
prepared. 

Experiment 13 

There is another method which is, however, not so 
good for artists' purposes, and that is the roasting of green 
vitriol (sulphate of iron). 

This substance is a salt of iron, as can easily be proved 
by dissolving a few of the green crystals in water, boiling 
with a few drops of hydrochloric acid and chlorate of 
potash, and then adding potassium ferrocyanide. A dark 
blue precipitate is at once produced. 

Experiment 14 

Grind up a few crystals of sulphate of iron into a coarse 
powder in the mortar, and heat them strongly for some 
time on a piece of platinum foil in the flame of a Bunsen 
burner. They will first of all turn white and then red in 
colour. Take a little of the red powder which is left and 
grind it in oil, and compare it with the roasted ochre. 

This is the second important way of preparing these 
reds, though it' may be questioned if they are as safe 
to use as those prepared from roasting ochres, and while 
they are lighter, they are somewhat harsher in colour. 

If a red is prepared in this way, it should be well 
washed with hot water and dried before being used for 
artists' purposes, as it may contain traces of acid com- 
pounds from imperfectly decomposed portions of the green 
vitriol. 

To prepare lighter shades, these red ochres may be 



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TERRE VERTE 29 

mixed with fine whiting (chalk), or fine gypsum (sul- 
phate of lime). This is a legitimate method of obtaining 
lighter shades, the intermixed substances being quite 
harmless, and the custom dating back as far as the 
fifteenth century, and probably much farther. 

After what has been said about the varieties in shade 
occurring among ochres, we naturally find the same to be 
true of the red ochres. 

Not only does each maker sell several different shades 
from light red to purple, but if the light red, Venetian 
red, or Indian red of different makers are compared 
together, they will be found to differ considerably in shade 
and brilliancy of colour. 

Burnt sienna is, of course, prepared in the same way 
by roasting raw sienna. 

This pigment is hard to grind, and requires to be 
ground very fine in order to bring out the rich glowing 
transparent tints of which it is capable. 

These red ochres are all absolutely permanent 
and do not affect other pigments. 

Terre Verte 

This is another pigment of a soft grey-green shade 
which owes its colour to iron. Unfortunately it is no 
longer obtainable of so fine a colour as the terre verte 
used in the fifteenth and sixteenth centuries, so that it is 
not used so much as formerly. 

Experiment 15 

\ Grind a little terre verte in water and in oil and note 
the colour. 



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3o 



PROCESSES, PIGMENTS, AND VEHICLES 



Expose a wash of the pigment to light. 

It is absolutely permanent and does not affect 
other pigments. 

It will be noted that all the pigments described up to 
this point owe their colour to iron. 

This is due to the fact that iron is able to combine 
with the oxygen of the air and with water to make 
several different compounds of different colours. 
If a piece of iron is exposed to damp air it rusts. 
This rust is a combination of iron with oxygen, whid^ 
is red in colour. 

In the same way the red ochres are all compounds of 
iron with oxygen, mixed with 
other things, and according 
to the amount of oxygen 
present, vary from red to 
purple in colour. That iron 
does combine with the oxygen 
of the air to form these ' red 
oxides/ as they are called, is 
easily proved by a simple 
and pretty experiment. 

The reader is already prob- 
ably familiar with the fact 
that air is a mixture of two 
gases, oxygen, the supporter 
of life and combustion, and 
nitrogen, which is inert, and serves to dilute the oxygen. 
The removal of the oxygen from the air by rusting iron 
can easily be shown in the following way : — 




REMOVAL OF OXYGEN FROM THE 
AIR 



Experiment 16 
Take a piece of stout copper wire and bend the bottom 



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TERRE VERTE 31 

into a circle so as to enable the wire to stand upright, and 
form the top into the shape of a little hook. 

Stand the wire upright in a dish of water and attach 
to the hook a bundle of clean iron filings free from grease, 
and steeped in a solution of salammoniac, and tied up in a 
piece of muslin. 

Place an inverted glass cylinder over the whole. Leave 
the apparatus alone for a day or two. 

As the iron rusts or combines with the oxygen, the water 

gradually rises in the cylinder, until it occupies about \ of 

*the whole volume of the cylinder. This means that all 

the oxygen has now been removed, as \ of the air consists 

of nitrogen. 

Now turn the cylinder sharply over and insert a lighted 
taper. 

The taper at once goes out, showing that the oxygen 
has been removed, and nothing but the inert nitrogen has 
been left. 

The green and yellow pigments which owe their colour 
to iron contain compounds of iron, oxygen, and water. 

This can easily be shown in the following way : — 

Experiment 17 

Prepare a solution of green vitriol and add ammonia to 
it. A green precipitate of iron, oxygen, and water com- 
bined together is at once thrown down. 

Now pour the whole solution and precipitate on a filter 
paper placed in a funnel, and allow the liquid portion to 
drain away, leaving the precipitate behind. 

(This operation requires a little explanation. 'Filter 
papers' are cut circular in shape, and are made of un- 
glazed porous paper. They enable liquids to be completely 



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32 PROCESSES, PIGMENTS, AND VEHICLES 

separated from solids suspended in them, the liquid 
escaping through the pores. If you wish to 'filter' a 
liquid, take one of the filter papers, fold it in half, and 
fold it again so that it is cone-shaped. 

Now open it out so as to make a little cone-shaped bag, 





FILTRATION 



fit it into a glass funnel, and pour in the liquid to be 
filtered. When a filter paper cannot be obtained, a piece 
of blotting-paper will do.) 

After filtering the liquid, open out the filter paper and 
leave the green precipitate exposed to the air. 

It will gradually turn of a brownish-yellow colour, thus 
showing the formation of another compound of iron, 
oxygen, and water, to which the yellow colour of ochre is 
due. 

This completes all we need know about ochres, and we 
can pass next to consider another group of earths, the 
umbers. 



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CHAPTER V 

THE UMBERS 

We have seen the importance of iron as a colouring 
matter, and we have now to examine a new substance, to 
which the colour of the umbers is largely due. 

The umbers contain compounds of iron, but associated 
with the iron are compounds of a metal, to which the name 
' manganese ' has been given. Possibly many of my readers 
have never heard of this metal before, and yet, though the 
metal itself in a pure state is of no value in the arts, its 
compounds are frequently used for various purposes. 

As we shall see when we come to study the preparation 
of oils, the compounds of manganese supply us with the 
most valuable kinds of dryers, by which boiled oils and 
drying oils can be prepared. In the meantime we shall 
only consider its importance as forming part of the 
colouring substance in the umbers. 

One of the commonest varieties of manganese is the 
black oxide ; this is found in large quantities as an ore, and 
has sometimes been used as a pigment. 

Experiment 18 

Take a little black oxide of manganese, note its colour, 
grind a little in oil and note the colour of the pigment 

D 



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34 PROCESSES, PIGMENTS, AND VEHICLES 

obtained. This metal is present in umber, arid gives umber 
its fine dark brown colour. 

The finest umbers come from Cyprus, though umber is 
also obtained in Devonshire, Derbyshire, Cornwall, Wales, 
and parts of France, Italy, and America. The pigment is 
obtained by mining, and is then ground with water and 
floated over, as we have already seen in the case of the 
ochres, dried, and is then ready for grinding in oil. 

On comparing the umbers sold by different makers, 
they will be found, like the ochres, to differ considerably 
in shade and in the quality of the colour. 

The finest Cyprus umbers have a greenish tint, which 
gives a brown of a peculiarly rich quality. 

Experiment 19 

Grind in oil and compare Cyprus umber with common 
umber, and notice the difference in the richness and quality 
of the colour. 

The umbers, owing to the manganese compounds they 
contain, act as powerful dryers, and consequently in some 
cases the pigment becomes hard and unusable in the tube 
from the action of the umber upon it. 

Experiment 20 

Grind a little Venetian red and a little raw umber in 
raw linseed oil, rub out a little of each on a piece of glass, 
and put the glass aside. 

Examine from time to time, and note which patch of 
colour dries first. 

Burnt umbers are of course prepared by gently roast- 
ing raw umbers; 



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CAPPAGH BROWN 35 

Experiment 21 

Gently roast a little finely-powdered umber on the iron 
plate used to roast yellow ochre, then grind a little in 
oil, and notice the warm red tint which has taken the 
place of the brownish green tint of the raw umber. 

Umbers are permanent, and do not affect other 
colours. 

Experiment 22 
Paint out a wash of umber and expose to light. 

Cappagh Brown 

This is an umber of a particular shade obtained in Ire- 
land. It is used to some extent by artists, and corre- 
sponds to the other umbers in its properties. 

Experiment 23 

Grind some Cappagh brown in oil and compare the 
tint with raw umber. 



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CHAPTER VI 

THE BITUMENS AND BITUMINOUS EARTHS 

In certain volcanic districts a tarry substance is found 
corresponding closely in its composition and properties to 
the black residue left in a retort on distilling coal-tar. 

This substance belongs to the group of organic sub- 
stances, and will burn in the air with a smoky flame. 

It is known as Asphaltum, and a special quality of it 
found in Palestine is known as Bitumen of Judea. It is, 
however, difficult to distinguish the artificial from the 
natural substance, and bitumens of various origins are 
used as pigments. 

Experiment 24 

Take a piece of Bitumen of Judea and a piece of 
asphaltum prepared from coal-tar, notice the appearance 
of each, and heat a little of each in the Bunsen flame. 

They both melt, then begin to boil, and then catch fire 
and burn with a smoky flame and a strong acrid smell. 

These substances, when ground in oil, yield beautiful 
transparent browns, which are permanent when exposed to 
light. 

They are of little use as water-colour pigments. 



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BITUMENS 37 

Experiment 25 

Grind the samples of bitumen both in water and in oil, 
note their appearance, and expose a wash of both to light. 

There is, however, a serious objection to their use in 
oil-painting, and that is the tendency they have to flow. 

These bitumens belong to an interesting class of bodies 
which are intermediate between solids and liquids. If 
struck by a sudden blow they are hard and brittle, and 
break up like a piece of glass. If, on the other hand, they 
are exposed to the slightest pressure for a long period of 
time, they gradually yield to it and flow like a liqiud. 

Experiment 26 

Melt some bitumen in a ladle over the fire, and pour it 
out into the round tin lid of a tobacco-box. When cold, 
place on the top of it a halfpenny and put it away. In 
the course of weeks, or may be months, the halfpenny will 
slowly sink into the bitumen by its own weight. 

It is for this reason that the use of this pigment has 
been given up, the most extraordinary results having 
followed from its reckless use by the painters of forty or 
fifty years ago, in some cases portions of the picture 
having actually slid down the canvas. 

At the same time there can be no doubt that it was 
successfully used by the 'old masters/ and apparently, 
judging by old receipts, their secret was to melt it over the 
fire and let it boil for some time, then take the hard mass 
left behind and grind that in oil. 

In this way a pigment is obtained of fine quality, 
though not so fine as that obtained from the ordinary 
bitumen, and requiring somewhat prolonged grinding. 



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38 PROCESSES, PIGMENTS, AND VEHICLES 

I am also disposed to think that if the bitumen is used 
as a very thin glaze it is not injurious, but the pigment has 
fallen into such discredit that it will probably be a long 
time before confidence is restored and artists feel safe in 
using it even after careful melting and boiling. This is, I 
think, a pity, as it has certain qualities which no other 
pigment can replace. 

We come next to a group of very dangerous brown 
pigments which are earths, and which owe their colour 
largely to the intermixture of bituminous substances. 

Though bitumen itself stands exposure to light, these 
bituminous earths do not do so, and consequently must be 
avoided. They are Vandyke brown, Cologne earth, 
Cassel earth. 

Of these, Vandyke brown is the one most used. Some 
varieties are free from bituminous substances, but are very 
poor in colour, and therefore valueless. 

Experiment 27 

Take a little dry Vandyke brown. Place it in a test- 
tube and heat strongly. Notice the tarry matters which 
distil off with strong acrid smell. 

Experiment 28 

Paint out a wash of Vandyke brown and expose to 
light. It will be found to slowly fade. 

This fascinating pigment is regarded as indispensable 
by some artists, while others regard its use as a proof 
of incompetence. There is no doubt it should be struck 
out from the palette. 

We have now dealt with the principal earths. 



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BITUMINOUS EARTHS 39 

There are no other natural pigments of practical im- 
portance, as the malachite greens (green copper ores) are 
little used, and real ultramarine, prepared from lapis lazuli, 
is a glorious but too expensive pigment. Of these I shall 
speak in the proper place, but must now proceed to con- 
sider the more important of the artificial pigments, and 
shall "begin with the whites. 



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CHAPTER VII 

WHITE LEAD (FLAKE WHITE), BARYTES, ZINC WHITE, 
LEAD SULPHATE 

We have already seen how iron in combination with the 
oxygen of the air yields a series of valuable pigments. 
We must now study briefly the properties of another 
gas which enters into the composition of white lead, and 
the name of which is probably familiar to us all, viz. 
carbonic acid gas. 

Experiment 29 

Place a few pieces of broken marble in a wide-mouthed 
4 bottle and pour on the top 

a little hydrochloric acid. 
At once the marble begins 
to dissolve in the acid 
with effervescence, bubbles 
of gas coming off. This 
gas is carbonic acid gas, 
which in combination with 
lime forms chalk and 
marble. 
After the acid has been acting on the marble for a few 
minutes, lower a lighted taper into the bottle. 




MAKING CARBONIC ACID GAS 



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WHITE LEAD 41 

The taper at once goes out, carbonic acid gas being 
inimical both to combustion and to life. 



Experiment 30 

Take some lime, shake it up with water. A little 
will dissolve. Filter the solution and keep in a corked 
bottle. Pour some of this clear solution or * lime-water ' 
into the bottom of another wide-mouthed bottle. Now 
take up the first wide-mouthed bottle which is full of 
carbonic acid gas, and go through the action of pouring 
from this bottle into the second, taking care not to tip 
it so far as to let any of the hydrochloric acid pour over. 




POURING CARBONIC ACID GAS 

The carbonic acid gas is a very heavy gas, much heavier 
than air, and so it pours over from the one bottle into 
the other. Now put your hand over the mouth of the 
second bottle and shake up the lime-water and carbonic 
acid gas together. A white precipitate of chalk or 
carbonate of lime is at once formed, the carbonic acid 
and the lime combining together, and the chalk being 
thrown down as it is insoluble in water. 

We have thus shown that carbonic acid gas 

(1) Pvis out a light 

(2) Is a heavy gas. 

(3) Throws down a precipitate with lime-watei\ 



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42 PROCESSES, PIGMENTS, AND VEHICLES 

Experiment 31 

Now, in the same way, pour hydrochloric acid on 
chalk, whiting, and washing-soda, and notice that in 
each case the same gas, having the same properties, is 
set free. 

Experiment 32 

Place some dry white lead in a bottle and pour on 
a little nitric acid this time (this is done merely because 
lead is more soluble in nitric than hydrochloric acid), 
and test the gas bubbling off. This gas will also prove 
to be carbonic acid, and if the sample of white lead is pure 
it mil completely dissolve in the nitric acid. 

We thus see that white lead is evidently a carbonate 
of lead and contains carbonic acid gas. 

Now we can understand how it is prepared. 

Experiment 33 

Take a little lead which has been 'granulated' by 
melting the lead and pouring it into water. 

Boil up a little of this granulated lead with acetic acid. 
It will slowly dissolve, forming a solution of 'lead 
acetate ' or c sugar of lead/ the most dangerous of all 
dryers. 

Add to this solution a solution of washing-soda which 
we have seen contains carbonic acid. A white precipitate 
of carbonate of lead comes down which we can filter, wash 
with water and dry. 

This is one variety of white lead. 

We have now seen that to make white lead we must 



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WHITE LEAD 43 

first attack and dissolve the lead with acetic acid, and 
then act on that with carbonic acid gas, and the result is 
white lead. 

I can now explain the best way of doing this, which 
is very interesting, being a process of unknown antiquity, 
which has been very slightly modified. 

The lead is first cast into gratings and the gratings 
are arranged over a lot of little pots containing acetic 
acid (in the old days vinegar was used), so that the 
vapour of the acetic acid can attack the metallic lead, 
to form lead acetates. The pots and gratings are next 
packed round with spent tan from the tanyard. This 
spent tan slowly ferments, and in fermenting gives off 
carbonic acid gas, which acting on the lead acetates 
converts them into lead carbonate. 

After some weeks the * stack' consisting of the piled- 
up pots and gratings is unpacked and the lead grids are 
found to have been changed into masses of lead carbonate ; 
this also contains a certain amount of a compound of 
lead, oxygen, and water (lead hydrate) which improves its 
qualities. 

The lead carbonate made in this gradual way is found 
to be of the best possible quality, being dense, of good 
covering power, and forming very durable coatings when 
painted outside and exposed to the weather. This 
process is known as the stack or Dutch process. 

There are other ways of making white lead, besides 
that described in Experiment 33, but they are none of 
them so good. 

White lead differs considerably in brilliancy and colour, 
the white lead made for house-painters not being nearly 
so white as the * flake white ' prepared for artists. This 
flake white is made from a specially pure lead, and the 



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44 PROCESSES, PIGMENTS, AND VEHICLES 

finest quality comes from Austria, and is known as 
Cremnitz white. 

Experiment 34 

Take two or three samples of dry white lead, and 
press them flat side by side with a spatula on a white 
plate and compare the whites one with another, for 
brilliancy and colour. 

White lead even of the finest quality is a little yellow 
in colour, and it is consequently a common practice to 
add a very little ultramarine (about 1 part in 10,000) 
to neutralise the yellow. A better plan, however, which 
is used by some artists' colourmen, is, to add a little oxide 
of zinc which is a white of a bluish tinge. In this way 
the yellow tint of the white is removed without diminish- 
ing the brilliancy of the pigment. 

When white lead is ground in oil it forms a peculiarly 
stiff firm mixture, quite different from that obtained by 
mixing ordinary pigments with oil. 

This is best seen by examining a sample of white lead 
ground in oil by machinery, as it is sold for house-painting 
purposes. The peculiar consistency is supposed to be 
due to the fact that a little of the oil combines with the 
white lead to form a lead soap, (Ordinary soap is made 
by combining an oil or fat with soda, a lead soap is 
formed by combining white lead with an oil or fat.) 

To the formation of this lead soap is attributed the 
tough leathery coating formed by white lead and oil when 
it dries. 

The covering power of white lead, that is, the quantity 
of the paint necessary to cover completely a given surface, 
is of great importance to house -painters, but does not 
matter so much to artists. 



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WHITE LEAD 45 

There is only one way of testing accurately the cover- 
ing power of a pigment, and that is to paint a surface 
over with black and white checks, and then see how 
many coats of paint, and what weight of paint, are required 
to paint out these checks when the paint is laid on by a 
skilled house-painter. 

Any other methods are delusive, though we can get 
a rough notion by merely grinding the pigment in oil, 
rubbing it out with the finger, and noticing how far it 
covers with colour the surface underneath. 

For covering large surfaces and preparing grounds the 
best quality of white lead prepared for house -painters 
is quite as good as the artist's flake white, the only 
advantage of the flake white being its greater whiteness 
and brilliancy. 

Experiment 35 

Rub out some white lead ground in oil on a piece of 
glass and put it aside to dry. 

When dry expose it to sulphuretted hydrogen gas as 
described in Experiment 9. It will at once turn dark 
brown. Now place it in the window and examine it from 
day to day. It will gradually bleach in the bright day- 
light. 

We learn by this experiment one of the great defects 
of white lead, its sensitiveness to sulphur gases. This 
makes it a somewhat unsuitable pigment for modern 
pictures which are exposed to the action of various sulphur 
compounds derived from coal gas, coal fires, sewer gas, and 
other sources, in large cities. 

On the other hand, a picture which has been darkened 
in this way can be to a great extent restored by placing it 
in the window and exposing it to bright daylight. 



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46 PROCESSES, PIGMENTS, AND VEHICLES 

White lead is no longer used for water-colour painting, 
and is gradually being given up for oil-painting. 

Though oil-paintings which have been so discoloured 
can be restored by exposing to daylight, this cannot be 
done in the case of permanent decorative work on 
walls. 

White lead should therefore never be used for 
paintings on the walls of buildings in cities. 

It may be used, however, in country buildings, where 
there is no gas and no polluted air. 

When an old water-colour painted with white lead has 
got discoloured, it may be restored by soaking blotting- 
paper in peroxide of hydrogen, and then pressing the damp 
paper on the surface of the picture. The peroxide of 
hydrogen at once bleaches the white lead. 

White lead has one very serious defect, it is a deadly 
poison. Artists using comparatively small quantities do 
not suffer from this, but those who manufacture the white 
lead are constantly the victims of lead -poisoning. The 
replacement of this pigment by non - poisonous whites 
would therefore prevent a great deal of human suffering, 
and it is to be hoped that the time when the manufacture 
of white lead will be abandoned is not far distant 

White lead is often adulterated for house -painters' 
purposes with barytes. This is a white mineral (sulphate 
of barium) which forms a pigment of poor covering power, 
but absolutely permanent. 

It is sometimes sold as permanent white. 

Experiment 36 

Grind a little barytes in oil, rub out, and notice the poor 
covering power. 



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ZINC WHITE 47 

Its presence in white lead can easily be detected if the 
white lead has been freed from oil 

It is insoluble in acids, and therefore is left behind in 
dissolving white lead in nitric acid. 

Experiment 37 

Mix a little dry white lead and barytes together and 
treat with dilute nitric acid. The white lead quickly 
dissolves and leaves the barytes behind. To prove this, 
after effervescence has ceased, pour the whole into a filter 
paper, wash the precipitate with water (this is done by 
filling up the filter paper with water, letting it drain 
completely away, and filling up again three or four times), 
then moisten the precipitate with sulphide of ammonium. 
It does not turn black, showing that the white lead has all 
been dissolved. 

Zinc White 

This is a very important white pigment for artists as it 
is not affected by sulphur compounds. 

Experiment 38 

Take some zinc white, mix it with water, and add 
ammonium sulphide. 
It does not change colour. 

Experiment 39 

Compare the colour of zinc white with flake white both 
dry and in oil, and note the blue shade of the zinc white. 



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48 PROCESSES, PIGMENTS, AND VEHICLES 

Zinc white is obtained by burning zinc, and is a zinc 
oxide. As manufactured it is poor in covering power, but 
by grinding under heavy edge runners a condensed zinc 
white is produced equal in covering power to the best white 
lead. 

Experiment 40 

Compare ordinary zinc white, condensed zinc white, and 
white lead ground in oil, by rubbing out, and notice differ- 
ence of covering power. 

Zinc white is now used for water - colour painting 
under the name of Chinese white. 

Sulphate of Lead 
Experiment 41 

Dissolve lead acetate in water and add a little dilute 
sulphuric acid instead of washing-soda as before (Experiment 
33) ; a white precipitate is thrown down. 

Filter, wash, and dry. 

This is lead sulphate which is now being used in the 
preparation of white pigments. 

Grind a little in oil and note the colour and covering 
power. 

Lead sulphate prepared in this way is poor in covering 
power. It is therefore either prepared by subliming lead 
ore or by grinding the precipitated lead sulphate with zinc 
oxide under heavy edge runners. 

The last process gives the best pigment. It is a pure 
white, a little blue in colour and covering as well as white 
lead. 

It is much less susceptible to sulphur compounds than 
white lead, and is practically insoluble in acids. 



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SULPHATE OF LEAD 49 

Experiment 42 

Grind a little lead sulphate in oil, allow it to dry and 
expose to sulphuretted hydrogen, as was done with white 
lead. 

Note the slight change produced. 

Warm lead sulphate with dilute nitric acid. It is 
almost insoluble. 

And for this reason it is very slightly poisonous, those 
manufacturing it not suffering from lead-poisoning. 

These zinc oxide and lead sulphate paints are now being 
brought before house-painters and artists under various 
names, such as * White Lead, Caledonia Park Works, 
Glasgow/ ' Freeman's White/ ' the New Flake White or 
Cambridge White/ * Marble White/ etc. 

They have the advantage of keeping their colour better 
in the impure air of large towns and gas-lighted rooms, but 
whether they will stand exposure out of doors as well as 
white lead is not yet ascertained. 

Zinc white prepared the old way was believed by 
artists to flake off, but these new whites have shown no 
such tendency. They are also practically non-poisonous, 
and free from the disagreeable smell of white lead. 



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CHAPTEE VIII 

SOME IMPORTANT ARTIFICIAL YELLOWS 

A LARGE number of the bright yellows are unfortunately 
fugitive, and there are only a few, therefore, which we 
need consider here. 



Chrome Yellows 

In the first place, the chrome yellows of various kinds 
must be considered, their preparation, and how far they 
can safely be used. 

Experiment 43 

Prepare a solution of barium chloride and of potassium 
chromate, and add the one solution to the other. A 
yellow precipitate of barium chromate or Lemon Yellow is 
thrown down. Wash the precipitate, dry, and expose a 
wash to light. 

It will be found to be permanent, and is therefore a 
safe pigment for artists to use. 

Unfortunately similar lemon yellows can be prepared 
from salts of strontium and of lead which are not so 
durable. Of these the lead lemon yellow is the cheapest 



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ARTIFICIAL YELLOWS 51 

Experiment 44 

Dissolve some lead acetate, sodium sulphate, and potassium 
bichromate in water and mix them all together. A yellow 
precipitate is thrown down, which is a mixture of the 
white lead sulphate with the yellow lead chromate. 

Wash, dry, and expose the pigment ground in oil to 
the action of sulphuretted hydrogen. It at once blackens, 
while barium chromate when tested in the same way does 
not alter. 

This shows clearly the unsuitability of Lead Chromates 
for artists' purposes. Every shade of lead chromate from 
bright scarlet to pale yellow can be prepared, but should 
all be avoided except for common house-painting purposes. 
They are known as Chrome Yellow, Orange, etc. 

Mixed with Prussian blue, lead chromate is used for 
making * Chrome Greens, ' and other cheap greens 
appearing under a variety of names. None of these is 
permanent. 

So Barium Chromate is the only chrome colour artists 
should use. 

The most important group of yellows are the 

Cadmium Yellows 

These may be prepared of various shades and by 
various processes. 

There is, however, one simple process by which, with 
little trouble, we can prepare several of these shades for 
ourselves. 

Experiment 45 

Dissolve 1 ounce of cadmium sulphate in water and 
add to it 1 ounce of sodium hyposulphite. Place over a 
lamp and boil gently. 



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52 PROCESSES, PIGMENTS, AND VEHICLES 

Gradually a pale yellow cadmium yellow will come 
down. 

After about one hour's boiling filter off the pale yellow 
precipitate, add 1 ounce of hyposulphite and continue 
boiling. Gradually an orange yellow will come down. 
After an hour filter off and boil again. A deeper orange 
shade will now separate. 

Wash and dry these three precipitates and expose to 
light. 

The pale shade mil fade, but the more orange shades will 
not change. 

This was supposed to be due originally to the presence 
of free sulphur in the pale shades, but this is not so, and 
the fading of these pale shades seems to be due to two 
varieties of cadmium sulphide. 

The practical result is that only orange shades of 
ordinary cadmium yellows should be used. 

There are two pale cadmiums in the market, however, 
both made by a secret process, viz. Winsor and Newton's 
Aurora Yellow, and Madderton & Co/s Daffodil, which are 
quite permanent. 

Cobalt Yellow (Aureoline) 

This yellow is made by a somewhat complicated 
process. It is permanent, and may be safely used. I 
shall not trouble you with the details of the manufacture 
here. 

Naples Yellow 

Formerly a compound of lead and antimony, now a 
mixed yellow. 

If made from proper ingredients, quite permanent. 



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ARTIFICIAL YELLOWS 53 

This practically exhausts the list of bright yellows, 
the yellow lakes, such as Dutch Pink and Italian Pink, 
being very fugitive, and Gamboge and Indian Yellow 
not being sufficiently permanent. 

The student should satisfy himself, however, on these 
points by making washes of all these pigments and 
exposing them to light. 

Dutch and Italian Pink are prepared from Quercitron 
Eark, some Yellow Lakes from Persian Berries, and Indian 
Yellow from Purree. 



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CHAPTER IX 

SOME IMPORTANT ARTIFICIAL REDS 

Let us first examine Vermilion. \ This magnificent 
pigment has been prepared artificially for at least five 
hundred years in Europe, and probably for a very much 
longer time in China. 

The old, and present Chinese, method is to sublime 
sulphur and mercury together, the red sulphide of mercury 
subliming and collecting in the top of the crucible 
cover. 

This is then subjected to grinding, floating over and 
washing. 

The modern method is to prepare a black sulphide of 
mercury, and then by heating with a strong alkali, like 
caustic potash, to convert it into the red variety. 

Vermilions prepared the modern way are not so pure 
chemically, sometimes contain injurious quantities of alkali 
and sulphur combinations, and are apparently not so per- 
manent. 

It is safer, therefore, to use real Chinese vermilion in 
painting. 

While vermilion seems to last for an unlimited period 
in ordinary rooms and galleries, it is injuriously affected 
by sunlight after some time. 



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ARTIFICIAL REDS 55 

Experiment 46 

Paint out a wash of vermilion and expose to sunlight. 
After a time portions will be found to turn black. 

Its durability, however, on old pictures seems to justify 
its use. The change of colour mentioned above is not 
due to air or moisture, but is simply due to the red 
variety of the sulphide turning into the black variety, and 
it seems to require the action of sunlight for some time 
to bring it about. 

The Madder Lakes 

Experiment 47 

Dissolve a little alizarine in ammonia (alizarine is the 
dyeing principle of the madder root, and is now artificially 
prepared from coal-tar), and add a solution of alum. 

A ruby red precipitate is thrown down and the violet 
colour of the liquid disappears. Compare this with the 
white precipitate obtained on adding alum to the ammonia 
without the alizarine. 

Wash and dry both precipitates and grind them in oil. 

The alum and ammonia alone give a precipitate of 
alumina, the base on which the lake is shuck. 

When alizarine is present, it dyes the alumina as it is 
coming down, thus giving it a ruby red colour. 

The alumina alone in oil gives a transparent, colourless 
jelly. 

The dyed alumina a ruby-coloured lake. 

Experiment 48 

Repeat the last experiment, only before adding the 
alum, put into it a drop or two of a solution of green 
vitriol (sulphate of iron). 



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56 PROCESSES, PIGMENTS, AND VEHICLES 

The lake thrown down will now be purple in colour. 

To another portion of alum add a drop or two of blue 
vitriol (sulphate of copper). The lake thrown down will 
now be brownish purple in colour. 

In this way we see how different coloured lakes can be 
obtained from alizarine and alumina. 

It is a matter of no moment whether the alizarine used 
be made by extracting it from the madder root or by an 
artificial process. 

Experiment 49 

Expose to light washes of madder lakes. 

They will prove remarkably permanent, the purple and 
rose madders showing slight changes, and the strong ruby 
reds showing no change at all. 

If madders alter or fade it is probably because some 
other dye, like cochineal, has been added to obtain a 
particular shade of colour. 

Cochineal Lakes 

These lakes are prepared with alum and the colouring 
matter of the cochineal insect, and are sold as Crimson 
Lake, Purple Lake, Scarlet Lake, and Carmine. 

They are all fugitive, and should not be used. The 
student should expose a wash of crimson lake, if he has 
not yet done so, and note change of colour and fading. 

Avoid all lakes except madder or alizarine lakes. 



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CHAPTER X 

SOME IMPORTANT ARTIFICIAL BLUES 

Experiment 50 
Prussian Blue 

Dissolve sulphate of iron in water, and add a few drops of 
nitric acid, and warm. 

Dissolve potassium ferrocyanide in water. 

Mix the two solutions. 

A precipitate of Prussian blue is at once thrown down. 

This pigment is fairly permanent and may he used in 
oil, but in water-colour its use is somewhat doubtful. 

On exposure to sunlight it becomes greener, and slowly 
fades, but on being placed in the dark the colour gradually 
comes back again. 

Wash out some of the colour and notice these changes. 

Cobalt Blue 

This pigment, which owes its colour to the metal cobalt, 
can be prepared as follows : — 

Experiment 51 

Moisten some dry alumina with cobalt nitrate and heat 
strongly on charcoal in a blowpipe flame. 



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58 PROCESSES, PIGMENTS, AND VEHICLES 

A bright blue powder is the result. 
The manufacture of cobalt blue is a government 
monopoly in Germany. 




The pigment is absolutely permanent. 
Paint out a wash of the colour, and observe the effect 
of light upon it. 

Cerulean Blue 

This pigment is closely allied to cobalt blue, and is 
absolutely permanent. 

Both these pigments are expensive, and therefore cheap 
tubes of colour claiming to be cobalt blue or cerulean blue 
should not be used. 



Ultramarine 

This pigment used to be extracted from lapis lazuli, 
and real ultramarine so prepared can be obtained at a very 



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ARTIFICIAL BLUES 59 

high price. It has, however, been replaced by 'artificial 
ultramarine. ' 

This substance is almost exactly the same in chemical 
composition, and though Mr. Holman Hunt has thrown 
doubt on its durability, the results of other tests show 
that if of good quality it is Quite Permanent. 

It is prepared by heating together soda., China clay, 
sulphur, and resin, under special conditions. 

Experiment 52 

The student should paint out a wash of the colour and 
note the effect of light upon it 

Indigo 

This blue, obtained from the indigo plant, is of great 
beauty for water-colour work, but unfortunately very 
fugitive. 

Experiment 53 

Paint out a wash of indigo blue and note the result. 



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CHAPTEE XI 

SOME IMPORTANT ARTIFICIAL GREENS 

One group of greens, the Chrome Greens, I have already 
dealt with : they are mixtures of chrome yellow and 
Prussian blue, and are not permanent. They must not be 
confused with oxide of chromium greens. 

There are two greens which are the oxides of the 
metal chromium, one the simple oxide, sold as ' Oxide of 
Chromium/ the other the compound of the oxide with 
water, sold sometimes as Oxide of Chromium and some- 
times as Viridian. 

The first is a pale opaque, and the other a blue trans- 
parent green. 

Experiment 54 

Heat gently some bichromate of potash and boracic acid on 
charcoal. Take the dark green fused mass and grind and 
wash. The residue is viridian. 

On heating more strongly the pale opaque variety will 
also be obtained. 

Both these greens are absolutely permanent and do 
not affect other colours injuriously. 

Expose a wash of each to light and note the result. 



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artificial greens 61 

Cobalt Green 

There are several cobalt greens, from pale opaque to 
bluish green transparent varieties. 

They are absolutely permanent and do not affect 
other colours injuriously. 



Experiment 55 

Prepare a wash of cobalt green, expose to light and 
note the effect. 



Emerald Green 

This green is a compound of copper and arsenic, and 
is thrown down on adding a solution of white arsenic in 
carbonate of soda to copper sulphate, and then treating the 
precipitate with dilute acetic acid. 

It is the most brilliant of all artificial greens and is 
very poisonous. 

It is permanent, but injuriously affects vermilion and 
cadmium yellow, and even if glazed over, these pigments in 
oil will slowly penetrate through the oil and destroy them. 

Probably an intervening coat of a spirit varnish would 
stop this. 

Experiment 56 

Mix emerald green and cadmium yellow, both ground 
in oil together, and keep to note the effect. 

Next expose a wash of emerald green to light and note 
the effect. 



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62 PROCESSES, PIGMENTS, AND VEHICLES 

Verdigris 

This lovely green was largely used by the ' old masters.' 
It must not be mixed with water or oil, as it gradually 
turns black, and is also susceptible to sulphuretted hydrogen, 
and attacks other pigments. 

It can, however, be used for decorative purposes dis- 
solved or ground in a spirit or turpentine varnish, and 
produces a very rich effect glazed over white or tinted 
surfaces. 



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CHAPTEE XII 
some important artificial blacks 

Bone or Ivory Black 

This is prepared by heating bones or ivory in a retort, 
and is a fine and absolutely permanent black. 

Lamp Black 

This black is not much used by artists, and was 
regarded with great suspicion by the sixteenth -century 
Italian painters. It is prepared by burning oil in a con- 
fined space, and collecting the black particles. Its 
principal use is for making printing ink. 

Vine Black 

This should be the charcoal of vine twigs or peach 
stones. It has then a fine blue shade. 

If made from common charcoal it is often tinted with 
indigo, a most pernicious practice. 

Other shades of charcoal black are also prepared from 
different woods, and from wine lees, etc. etc. 



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64 PROCESSES, PIGMENTS, AND VEHICLES 

Experiment 57 

Heat a little indigo in a test-tube and note the purple 
vapour. In this way the presence of indigo in vine blacks 
can be detected. 

All these pure blacks are permanent and do not 
affect other colours. 



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CHAPTEE XIII 

OILS 

Experiment 58 

Take some linseed and crush it in a mortar. Place the 
crushed seed in a bottle with some light petroleum spirit. 
Shake it up and let it stand for some hours, then pour off 
the petroleum through a filter into a flask, and place the 
flask in boiling water. The petroleum soon boils off and 
leaves the oil which it has dissolved out of the seed 
behind. This is linseed oil. 

In the same way a small sample of nut oil from 
walnuts, and of poppy oil from poppy seeds, can be 
prepared. 

On a large scale these oils are prepared by exposing 
the seeds to tremendous pressure after they have been 
ground, the oil being thus squeezed out. 

Linseed Oil 

This oil is of the finest quality when it is pressed from 
the cold seed. It is then of a deep golden yellow colour. 
The common quality pressed from hot seed is of a brownish 
tinge. 

F 



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66 PROCESSES, PIGMENTS, AND VEHICLES 

The oil after extraction is still far from pure, containing 
various impurities which have been squeezed out from 
the seed along with the oil. 

These impurities are best removed if the oil is to be 
used for artists' purposes in the following way : — 

Experiment 59 

Take a clean glass bottle, put some sand in it, and 
then fill one-third of the bottle with salt water and one- 
third with the linseed oil to be refined. 

Cork the bottle, shake up the contents thoroughly, 
loosen the cork so that air can get in, and place the bottle 
outside on the ledge of a sunny window. 

Every morning for a week shake up the contents of the 
bottle vigorously. 

Gradually a white flocculent substance separates from 
the oil and is dragged out partly by the sand. After one 
week of this vigorous shaking leave the bottle alone on the 
window-sill for five or six weeks. 

At the end of that time the salt water will be full of 
a flocculent precipitate, and the oil above will be clear 
and of a pale golden colour. 

Now draw the oil carefully off by means of a siphon 
made of a piece of tin gas tubing, or a piece of glass 
tubing, bent into a suitable shape by warming the glass in 
an ordinary gas flame, and filter the oil through a filter 
paper. (The coarse grey filter papers are best for 
this.) 

The oil is now ready for use, being refined raw oil. 

The bleaching may, however, be carried further, the oil 
ultimately becoming almost colourless. 

Nut oil and poppy oil can be refined in the same way, 



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OILS 67 

but do not require bleaching, as they are nearly colourless 
oils to start with. 

Raw oil is used to grind colours with, some colourmen 
using linseed oil for all their colours, some preferring nut 
oil or poppy oil, especially for delicate blues and whites. 

It must be remembered, however, that all oils yellow 
with time on a picture. 

In order to get the colours of a nice consistency when 
being ground in oil, a little alumina (see preparation of 
lakes) may be added along with the pigment to the oil. 
This will give a stiff crisp mass, neither treacly nor sticky. 

Other substances are also used for this purpose, but 
alumina is perfectly harmless, and is therefore, if pure, 
very suitable for stiffening the colours. 

Raw oil, though best for grinding most colours, ' dries ' 
very slowly. 

It is therefore often necessary to use as a medium an 
oil which will dry faster. 

For this purpose a ' boiled oil ' is prepared. 

Experiment 60 

Place some refined raw linseed oil in two little glass 
flasks, add a little red lead to the one flask and a little 
borate of manganese to the other. 

Keep them very gently boiling over a lamp for four or 
five hours. 

Take a clean glass plate and put on it a drop of raw oil, 
a drop of the oil boiled with red lead, and a drop of the 
oil boiled with borate of manganese. Rub out each drop 
with the finger, put the plate away, and examine from 
time to time. The two boiled oils will ' dry ' quickly, 
while the raw oil will remain liquid. 



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68 PROCESSES, PIGMENTS, AND VEHICLES 

This 'drying/ as it is called, is really due to the oil 
being oxidised into a resinous substance, and is a process 
peculiar to certain oils called for this reason drying 
oils. 

In course of time the drop of raw oil will also c dry,' 
while a drop of olive oil under the same circumstances will 
never dry. 

Both these boiled oils evidently are now quick drying 
oils, but the one has a great advantage over the other, as 
can be shown by the following experiment. 

Experiment 61 

Expose the glass plate with the dried patches of oil to 
sulphuretted hydrogen gas. The oil boiled with red lead 
at once darkens, because the oil has dissolved some of the 
lead, while the oil boiled with manganese borate shows no 
change. 

For artists' purposes, therefore, only oils boiled with 
some compound of manganese should be used. Several 
compounds of manganese may be used for this purpose, 
and you will remember that umber, which contains man- 
ganese, acts as a dryer. 

In many old MSS. sulphate of zinc is recommended as a 
dryer. It really has very little or no effect, but there is 
reason to believe the sulphate of zinc formerly used was 
an impure variety containing manganese, so that manganese 
dryers, far from being a modern discovery, probably date 
back to the fifteenth century at least. 

Drying oils form a resinous coating which, when first 
formed, is tough and elastic, but in course of time gradu- 
ally grows hard and brittle, so that ultimately an oil 
picture becomes very fragile and easily destroyed. 



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OILS 69 

It has the advantage of forming a transparent medium 
which is easily manipulated, and at the same time 'partially 
protects the pigments from the action of air, moisture, and 
injurious gases. 

That it is penetrable by gases our earlier experiments 
with sulphuretted hydrogen have shown us. 



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CHAPTEE XIV 

VARNISHES 

Varnishes are prepared from gum resins which exude 
from certain trees, and come from various parts of the 
world. 

Of these, the most important to artists are — 

Amber. — A fossil resin found in the Black Sea and 
other places. This is the hardest of all the resins, and the 
most difficult to fuse. It is supposed to give the most 
durable varnishes. 

Copal. — This is also a fossil resin, and is found hi 
certain parts of Africa. It is exported as Sierra Leone or 
Zanzibar copal. Other so-called copals are softer and 
inferior resins. 

Sandarac. — This name was originally applied to the 
resin of the juniper. It is now applied to the resin 
obtained from a coniferous plant found in Algiers. It is 
soft, easily dissolved, and forms useful varnishes. 

Mastic. — This resin is obtained from a small tree 
(Pistacia lentiscus) found in the Greek Archipelago. It is 
a very soft resin, and dissolves easily -in turps or spirits of 
wine. 

Venice turpentine. — This is a balsam or liquid resin 
obtained from the larch. 



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VARNISHES 71 

Canada balsam. — This substance, which is practically 
the same in its properties as Venice turpentine, is obtained 
from a similar tree in America. 

Oleo de Abezzo. — This is the balsam of the silver pine. 
It was formerly largely used for preparing varnishes, and 
is repeatedly mentioned in old Italian receipts. It is not 
now an article of commerce. 

Dragon's blood. — This resin is of a deep red colour. 
The best quality is in sticks tied up in fibre. The inferior 
quality is sold in lumps. 

Aloes. — This is of a dark brown colour. 

Gamboge. — This is of a bright yellow colour. 



Varnishes 

Varnishes can be divided into two groups, oil varnishes, 
and spirit or turpentine varnishes. 

Oil varnishes are made by dissolving a resin in ail. 

Spirit varnishes are made by dissolving a resin in spirits 
of vrine, and terpentine varnishes by dissolving a resin in 
twpentine. 

In the case of spirits of wine and turpentine the solvent 
more or less completely evaporates and leaves a skin of 
the resin behind. 

In the case of oil varnishes, the oil ' dries,' forming a 
skin composed partly of oil and partly of resin. 

Experiment 62 

Take two small round-bottomed hard glass flasks. Put 
a little boiled oil in one and heat it over a flame. 

When the oil is hot, put some powdered copal in the 



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7* 



PROCESSES, PIGMENTS, AND VEHICLES 



second flask and heat it strongly over a flame till all 
the copal is melted. Then begin to add the hot 
oil little by little, stirring vigorously by swinging the 
flask (it can be held with a piece of cloth round the 
neck). 

When about three times as much oil has been added 

in volume as there is 
copal, place the flask 
back over the flame 
and heat it again. Dip 
in a glass rod into 
the varnish from time 
to time and put the 
drop removed on a 
glass plate. 

At first the drop 
on touching the glass 
plate will quickly turn 
milky in appearance, 
but after the heating 
has been continued for a short time, the drop on cooling 
will remain clear. 

The varnish is now finished, remove it from the flame, 
let it cool a few minutes, and add little by little, with 
vigorous shaking, about an equal volume of turps. Filter 
through a piece of muslin into a bottle. 

If this operation has been successfully performed a 
light - coloured clear varnish is obtained, which, though 
doubtless improved by keeping, will, if used at once, dry 
into a hard transparent glossy surface. 

Amber varnish can be prepared in the same way, but 
is rather dark in colour. 

Many receipts have been given for preparing a light- 




MAKING VARNISH 



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VARNISHES 73 

coloured amber varnish, but I only know one which is 
successful. 

With all the others, either little or no amber is dis- 
solved, or the solution obtained is dark. 

The one successful method is to dissolve the amber 
(finely powdered) in chloroform, and then add turps 
carefully to this solution and a little oil, then place in a 
flask and distil off the chloroform, leaving the amber 
dissolved in the turps and oil. 

There is, however, no reason to believe that a varnish 
prepared with hard Sierra Leone copal is not as good as 
amber varnish. 

There are other so-called copals which are of little 
value, the student should therefore notice the appearance 
of the genuine article. Oil varnishes of the other resins 
can be prepared in the same way. 

Spirit or turpentine varnishes can be formed by putting 
the powdered resin in a flask, covering it with turps 
or spirits of wine, fitting a cork loosely to the neck 
and placing the flask in boiling water. The resin will 
gradually dissolve, if it is soluble in these substances. 

Sandarac and mastic can both be dissolved in this 
way. 

Experiment 63 

Take of powdered mastic 7 ounces, of Canada balsam 
1 ounce, of turps 22 ounces, and warm them gently to- 
gether by placing the flask in boiling water. When the 
mastic is completely dissolved place a loose plug of cotton 
wool in the bottom of a glass funnel, and rapidly filter 
the varnish into a clear dry bottle, cork and keep for 
use. 

This is the best varnish for finished pictures, simply 



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74 PROCESSES, PIGMENTS, AND VEHICLES 

because it is very easily removed. When dry, rubbing with 
the palm of the hand or a little spirits of wine and cotton 
wool will remove it. 

Consequently a picture varnished with it is easily 
cleaned without injury to the picture underneath. 

This is impossible if an oil varnish has been used. 

Never varnish a picture till at least six months 
after painting it. 

Shellac dissolved in spirits of wine makes a nice 
varnish for leather and general purposes of that kind, 
and if gum lac be used, which is the crude shellac, a 
fine red varnish is obtained. Sometimes coloured varnishes 
are required for decorative purposes. 

For these, aloe gum gives a nice brown, and dragon's 
blood a fine red, while gamboge gives a beautiful 
yellow. 

To prepare them, put some Canada balsam, or ' Venice 
turpentine ' in a round-bottomed flask, heat, and then add 
the powdered aloes, dragon's blood, or gamboge, in the 
required quantity. They will dissolve in the melted 
turpentine or balsam. 

Next add some powdered sandarac. This will also 
dissolve readily. The weight of sandarac should be 
roughly equal to the weight of balsam. Then remove 
the flask from the lamp and dilute with turps. If this 
is too brittle a varnish for the purpose required, a little 
boiled oil must be added and thoroughly incorporated 
by heating with the other ingredients. 

A beautiful green varnish is obtained by dissolving 
verdigris in ' Venice turpentine.' 

Coloured varnishes are now made by dissolving aniline 
dyes in the varnish. I cannot speak, however, as to their 
durability, not having tried them, and the colouring matters 



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VARNISHES 75 

I have described have the merit of antiquity, being taken 
from old receipts. At the same time, very little, if any, 
boiled oil should be added, as the addition of oil means a 
more or less porous medium, and the colours are no longer 
so well protected from moisture. 

Verdigris, for instance, is permanent in Venice tur- 
pentine alone, but fugitive in oil alone. 

I have already said that mastic in turps is best for 
varnishing pictures. Copal in oil is a very durable 
varnish, and may be used with advantage as a medium, 
or for varnishing some surface which requires a very 
durable elastic coating. But as already explained, its 
durable qualities are the very reason why it should not 
be used for varnishing pictures, as when dirty it is so 
difficult to remove that the picture is almost certain to be 
injured in the process. 

Wax 

Sometimes, in preparing a special medium, beeswax or 
paraffin wax is used. 

Either of these substances has the property of making 
the colour they are mixed with dry dead. 

Consequently they are of use when oil colours are 
used for wall decoration, and where a dead surface is 
required. 

I describe elsewhere how such mediums are used, 
but I shall say here a word or two about their prepara- 
tion. One of the best known is M. Gambier Parry's 
medium. 

Professor Church thus describes its preparation. Warm 
8 ounces of oil of spike in a flask to 80° C, then add 2 
ounces of 'gum elemi.' Filter. Pour on the filter 2 



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76 PROCESSES, PIGMENTS, AND VEHICLES 

fluid ounces of turpentine heated to 80° C, and mix the 
two filtrates. 

Heat the mixed liquids, melt 4 ounces of white wax and 
pour into the liquid in a thin stream. When the mixture 
is complete, add gradually 16 ounces of oil copal varnish 
with vigorous shaking. 

This medium can be used to grind the colours in, and 
thinned down with turps to paint with. 

Professor Church also describes another medium of his 
own devising. 

4 ounces of paraffin wax are dissolved in 12 fluid 
ounces of turpentine. Heat till paraffin is thoroughly 
dissolved ; then add 1 6 fluid ounces of oil copal varnish 
and warm and shake till thoroughly incorporated. 

This medium has the advantage over the other of being 
simpler to prepare and not containing the gum elemi, 
which is a doubtful ingredient at the best. 

On the other hand, the paraffin wax has a bad habit of 
crystallising out from the mixture instead of remaining 
blended with it, as beeswax does. 

In my opinion the best medium for wall-painting is 
Professor Church's medium with beeswax instead of 
paraffin wax. 

Diluting Mediums 
Three are used by artists. 

Turpentine, Oil of Spike, Petroleum 

Of these, petroleum is probably the safest as it evapor- 
ates clean and leaves no resinous deposit if it has been 
properly rectified. To test this, moisten a piece of writing- 
paper with it and then expose it to the air. 



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VARNISHES 77 

The petroleum should evaporate without leaving any 
greasy stain. There is, however, no ' serious objection to 
the use of turpentine or oil of spike. 

Turpentine is obtained by distilling the fluid balsam 
obtained from the pine. 



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PART n 

NOTES ON 'PROCESS,' AND ON TEMPERA, 
FRESCO, WATER-COLOUR, AND OIL-PAINTING 



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CHAPTER XV 

DRAWING FOR PROCESS 

Photographic methods of reproduction are now being 
so largely used in place of woodcuts, or engravings on 
copper and steel, that it seemed of importance in a work 
of this kind to say something about the actual processes 
used in reproduction, in order that those engaged in draw- 
ing for ' process ' should understand something of what is 
done with their work, and what the limitations of the 
different methods are. In this way it is to be hoped an 
artist will be able to work more intelligently for the 
photographer, and consequently obtain more satisfactory 
results. To treat of etching, or engraving on copper and 
steel, would be impossible in a little book like this, but a 
good deal of useful information can be given for those 
who are drawing for ' process/ 

There are several leading methods of photographic 
reproduction and innumerable modifications of these, 
almost every firm engaged in this class of work having its 
special methods, usually dignified by a special name. To 
deal with all these is, of course, impossible, but some of 
the leading methods can be described, with a view to 
assist and guide the artist through the maze of slightly 
differing processes employed. 



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82 



PROCESSES, PIGMENTS, AND VEHICLES 




DIAGRAM OF CAMERA AND OBJECT 



In the first place, we may begin by briefly pointing out 
the different stages by which an ordinary photograph is 
produced, with a view to making clear, further on, the 
methods of photographic reproduction. On visiting a 
photographer 'to have a likeness taken/ one is placed before 

the camera. In the 
front of the camera 
is an arrangement 
of lenses, by which 
an image of the 
sitter is thrown on 
the back of the 
camera, and placed 
in the back of the camera is a glass plate, covered with a 
thin coating of a preparation which is sensitive to light. 
After the image of the sitter has been allowed to fall for 
a brief period of time on the sensitive plate, the plate 
is removed to the ' dark room/ and treated with a ' develop- 
ing solution/ The result of treatment with this solution 
is to bring out the image of the sitter on the sensitive 
plate, but an image in which all the lights and shadows 
are reversed. For where the lights fell on the plate, 
there the sensitive surface was most affected ; and where 
the shadows fell on the plate, there the surface was least 
affected. 

If, after the glass plate with its film has been put 
through another process, known as ' fixing/ we hold it up 
to the light, we find the image of the object photographed 
upon the surface, the shadows of the original object 
being represented by clear glass, and the lights of the 
original object by dark opaque portions. This glass plate 
with the image upon it is known as the ' negative/ 

In order to obtain a ' print ' from this negative, a piece 



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DRAWING FOR PROCESS 83 

of paper, coated with material sensitive to light, is placed 
under it, and the whole exposed to the sun. In a short 
time the light passing through the negative stamps the 
image on the sensitive paper. But now the lights and 
shadows are arranged as they were in the original object, 
the paper being darkened where the light passed through 
most easily; that is, where it passed through the clear 
glass portions of the negative, and remaining light in colour 
where the light was stopped by the opaque dark portions 
of the negative. In this way a picture or any number of 
pictures of the original object can be produced by putting 
one piece of paper coated with sensitive material after 
another under the negative and exposing to light. Thus 
the photographer produces the ordinary ' prints ' which are 
mounted and sold. If he wished to reproduce a black-and- 
white drawing he would do so in the same way, by 
placing it before the camera, obtaining a negative of it, 
and then ' printing ' off copies in the way described. 

This, however, would be a tedious and expensive 
method of going to work, and consequently much ingenuity 
has been spent in devising methods whereby the action of 
the light can be made use of to obtain an engraved block 
of the original drawing which can be placed in the printing 
press, and used to reproduce the drawing over and over 
again. It was also necessary to devise a process which 
could produce an impression of such a character that it 
could be set up and printed off along with ordinary 
type. 

There are many different methods of obtaining this 
result, but a very large number of them are based upon a 
peculiar property of a film of gelatine, or albumen, or 
bitumen, when exposed to light under certain conditions. 
For instance, it has been found that if a film of gelatine 



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84 PROCESSES, PIGMENTS, AND VEHICLES 

is first steeped in a solution of * bichromate of potash ' and 
then exposed to light, it becomes insoluble in hot water. 
Similarly, albumen and bitumen properly prepared can be 
rendered insoluble. This fact is the basis of most repro- 
ductive processes, and we can now proceed to the descrip- 



PROCESS BLOCK. LINE WORK WITH NO HALF-TONES 

tion of the production of a process block of a line-drawing, 
without any half-tones. The artist's drawing is illuminated, 
usually by an electric light, and placed outside a camera 
and a negative obtained, just as in ordinary portrait 
photography, with this difference, however, that usually a 
collodion plate is used instead of a gelatine plate. From 
this negative the next step in the process starts. If we 
examine this negative we shall find, as already explained, 



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DRA WING FOR PROCESS 85 

that the black lines of the original drawing are represented 
by clear glass on the negative, and the white paper by 
black opaque portions. This film is now stripped off and 
reversed. A film of albumen is laid over a zinc plate and 
rendered sensitive to light by means of bichromate of 
ammonia, and is then exposed to light under the negative. 
The result of this treatment is that all the parts of the 
negative which are transparent allow the light to pass 
freely through and render these portions of the albumen 
insoluble ; while the dark opaque portions of the negative 
protect the albumen underneath and leave these portions 
soluble. Consequently the insoluble portions correspond 
to the black lines in the original drawing, and the soluble 
portions correspond to the white paper in the original 
drawing. This film of albumen is then washed with cold 
water, so as to wash away the soluble portions, leaving the 
other portions on the zinc plate. This zinc plate, after 
protecting with bitumen, is next put in a bath of acid and 
etched, the portions exposed by the removal of the albumen 
being eaten away, and the other portions protected by the 
insoluble albumen, and corresponding to the original lines 
on the artist's drawing, being left. 

After several etchings the block is cleaned, and used 
like a wood-block for printing. 

In this way a line-drawing is reproduced by 'pro- 
cess/ 

In order to obtain satisfactory results from this method 
of reproduction, it is essential that the artist obey certain 
rules in doing his part of the work. In the first place, 
he must select a paper which is smooth and close-grained 
without any shine on the surface. Bristol board does 
very well. Then he must use a very black ink. One of 
the best inks for the purpose is Stephens' ebony wood stain, 



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DRAWING NEARLY ORIGINAL SIZE 



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DRAWING FOR PROCESS 87 

which, though manufactured for a different purpose, is 
very largely used by black-and-white artists. 

Then the drawing is usually considerably larger than 
the finished block is to be. Usually the block is not 
more than one-third of the size of the artist's drawing. 
This reduction in size must not, however, be pushed too 
far, as it results, unless the drawing is from a very 
skilful hand, in spoiling the final picture. 

But it is above all things important that every line 
should be clear, definite, and black, and sharp in outline ; 
that the artist, keeping in mind the fact that his drawing 
is going to be reduced, should not blur anything or put 
in any unnecessary lines, but should rather study the art 
of leaving out every line not absolutely essential for his 
purpose. His finished drawing should bear being looked 
at from some little distance, and should be done with a 
view to simple bold effects, without too much detail or 
minute work. The illustration shows a portion of an 
artist's drawing reproduced full size, while next to it 
is the whole drawing after reduction. By examining 
carefully these two illustrations, the beginner will learn 
more about how to draw for process, than can be learnt 
from mere verbal description. 

Having now described in an elementary manner the 
reproduction of line work by process, the next thing to 
be mentioned, following a due order of increasing com- 
plexity, is 'stippling.' Sometimes the artist having 
completed a line-drawing wishes certain portions softened 
by a half-tone. He indicates this by shading them with 
a blue pencil. The photographer then introduces mechani- 
cally dots or lines to produce the half-tone required. 
This is sometimes effective in drawings where simple broad 
treatment is required, or in designs, as it enables the lines 



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SAME DRAWING REDUCED : PROCESS BLOCK WITH NO HALF-TONES 



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DRAWING FOR PROCESS 89 

to be deeply etched in, which cannot be done in the case 
of half-tone work, which, as will presently be explained, 
does not lend itself so readily to sharp contrasts of black 
and white. This stippling process leads us naturally to 
half-tone blocks and their method of production. 

In order to produce half-tone it is necessary that the 



STIPPLING KNOWN AS 'ttESIN GRAINS' IN SKY 

half-tones on the block be represented by minute dots or 
lines, which are larger or smaller as the half-tone is darker 
or lighter. 

The conditions of printing will at once reveal this 
necessity. An ink roller is run over the block and then 
the paper pressed on it to take up the ink. Where there 
are portions in relief the ink remains and is transferred on 



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90 PROCESSES, PIGMENTS, AND VEHICLES 

to the paper. Where there are hollows the ink does not 
go, and the paper remains white. When dealing with a 
line-drawing, therefore, the whole matter is very simple, 
but half-tones require evidently some special treatment of 
the block to be reproduced on the printed page. In the 
case of etching, engraving, and woodcutting, the half-tones 
are obtained by the nearness or distance apart of minute 
lines, hatchings, or dots, and varying thickness of line. 

In the same way, in preparing a process block for the 
printer, the half-tones must be represented by minute 
lines or dots, near together or far apart, according to the 
amount of shade or light required. The problem before 
the photographer is, how can this result be obtained from a 
drawing consisting of continuous gradations of tone ? This 
problem has been solved in a most ingenious manner. 

When the picture is placed before the camera there is 
interposed between it and the sensitive plate a fine screen of 
some kind, usually consisting of glass plates upon which 
fine lines have been ruled so as to produce a minute 
network. This breaks up the continuous tones of the 
picture into minute dots, giving varying opacity with 
varying size, and when the plate is afterwards etched it 
is eaten out into a fine pattern, leaving the plate, where 
etched deeply, covered with minute points of metal some 
distance apart ; while, where not etched deeply, the little 
points of metal are broader and almost touch each other. 

If the negative had been exposed under the screen to 
an uniform light, say from a sheet of white paper, the 
final print would have been a white to grey or black 
surface, quite uniform, and made up of little dots of ink. 
The amount of light in the grey would have varied accord- 
ing to the length of exposure. But by also placing before 
the negative the artist's drawing, some portions of the 



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DRAWING FOR PROCESS 91 

negative are protected from light more than others, and 
consequently on the zinc plate the gelatine is left on some 
portions to a greater extent than on others, and so retards 
the etching process. 

If any half-tone process print is examined closely it at 
once resolves itself into a regular pattern, thus revealing 
the secret of its manufacture. 

Now there are serious difficulties in this half-tone work 
which somewhat limit its capacities. If the etching is 
carried far the stability of these minute points of metal 
is endangered, and they are likely to be completely eaten 
away. The result is that the plate is very lightly bitten 
in, and the final surface is in very low relief, thus differing 
from line work, where the plate may be safely bitten in to 
a considerable depth, and requiring very careful printing. 

Consequently, though remarkable results giving plenty 
of contrast have been obtained by careful working and 
printing, and delicate half-tones are also obtained, there is 
a great want of contrast, and there are no pure whites or 
deep blacks in the ordinary commercial work. The artist 
should therefore recognise the limitations of the process 
from the first* and not ask from it what it cannot do. The 
illustration shows a specimen of half-tone process work. 
The effect is pleasing though wanting in contrast, for the 
reasons already given. But the artist can do more. He 
can assist the process over its weak points by his treatment 
of the subject. Instead of having one tone gently passing 
into another, he should emphasise the difference between 
each tone employed in his drawing and exaggerate it. 
Especially should this be done in the tones next to black 
and next to white. A considerable gap should be left 
here which, while throwing his drawing out, as a picture, 
will tend to prevent too much flatness in the finished print. 



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DRA WING FOR PROCESS 93 

It is usual in doing half-tone work to first tint the 
paper over with a slight wash of neutral tint> then put 
in the drawing with the brush, using lamp black, which 
gives a nice grey, in preference to Indian ink, and using 
Chinese white, remembering to exaggerate the effects as 
described above. Care should also be taken that no por- 
tions dry shiny. As said before, commercial half-tone 
process work is very limited in its capacities, but it can 
be helped by the printer as well as by the artist. By 
carefully * backing ' certain portions the printer can vary 
the pressure of the paper on the block and obtain in that 
way greater variety of light and shade. 

Where delicate gradations of tone are wanted, along 
with sharp contrast, it can only be obtained commercially 
by resorting to the wood block. Woodcutting alone pro- 
duces a block which can be printed with ordinary type, 
and which at the same time gives the artist a wide range 
of treatment. Commercial process produces line work 
with great perfection, and within certain limitations, due 
to bad printing principally, produces very pleasing half- 
tone work, but the wood block must be resorted to for 
many effects. These two illustrations show the same 
drawing treated by process and by woodcutting, and 
bring out very clearly the defects of the process work. 
Of course, photography is now employed by the wood- 
cutter. A photograph of the drawing is taken on the 
block of wood to guide him as to what to cut away and 
what to leave. We have then three methods of repro- 
ducing the artist's work in such a form that it can be 
printed off with ordinary type, namely : 

Process blocks for line-drawings with or without 
stippling, as required by the artist. 

Woodcuts. Process blocks for half-tone. 



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PROCESS BLOCK TOUCHED UP ON HIGH LIGHTS WITH A GRAVING TOOL 



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DRAWING FOR PROCESS 95 

One of the first things, therefore, which an artist has to 
decide is how he proposes to treat a subject, keeping these 
three processes in view, by which his work will be repro- 
duced, selecting the one from the first which will give 
him the results he requires, and working for that process 
in every stroke of the pen or brush. It is only in this 
way that satisfactory results can be obtained in the final 
print. 

Besides these methods of reproduction which have 
been already described, the half-tone process is used for 
line work to give softness to the line, and in many cases 
the half-tone block when complete is handed over to the 
engraver to work up. This has been slightly done in the 
illustration facing this page, but is done to a greater 
extent in some of the American work. Fine results are 
also obtained by making a large woodcut and photograph- 
ing down from it to make a process block. It is only fair 
to say in conclusion that half-tone process claims to give 
the widest range of any method for accurate reproduction 
of artists' work, and seems to do so in the hands of a good 
workman, though the ordinary commercial work is so poor. 

Besides the production of process blocks by the methods 
already described, there are other methods of photographic 
reproduction, which do not lend themselves to printing off 
with type, but partake more of the nature of lithographic 
methods of reproduction, or the obtaining of impressions 
from a copper plate, each picture having to be printed off 
by itself in a special machine, after careful preparation. 

Of these one of the most important is 

Collotype 

There are about forty varieties of collotype in use under 
different names, but the underlying method is the same. 



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DRA WING FOR PROCESS 97 

A negative is taken of the drawing as before, and a thin 
film of gelatine, is spread on a sheet of plate glass, 
rendered sensitive to light, and then exposed under the 
negative. It is then placed in cold water. The cold water 
is unable to dissolve the gelatine, but is absorbed and causes 
the gelatine to swell. On the parts of the film which have 
been protected from .light this swelling process can go on 
practically unhindered, but on the parts which have been 
exposed to light the swelling of the still soluble gelatine 
underneath is retarded by the insoluble film on the top, 
which results in the crinkling of the surface. To a certain 
extent this crinkling takes place all over the film, but prin- 
cipally over the insoluble portions, which consequently 
take up more ink, after the film has been dried. The 
result is that a collotype picture has a very slight irregular 
grain in it, quite different from the harder regular pattern 
of a half-tone process block, and half-tone is reproduced in 
it with great perfection. 

It is a troublesome process to work, and the artist 
must be careful in the selection of his paper, and in avoiding 
shiny places, especially on the high lights ; but it reproduces 
with far more delicacy and accuracy the half-tones of the 
original work than the commercial process block. Besides 
collotype there is 

Photogravure 

Photogravure is photographic etching in intaglio. The 
copper plate is prepared with a film sensitive to light, and 
after exposure, and the washing away of the soluble por- 
tions, the plate is bitten in, as a copper plate would be 
bitten in to produce an etching. It is used principally for 
reproducing pictures and etchings, and is the most difficult 
of these photographic processes, requiring great skill on 

H 



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98 PROCESSES, PIGMENTS, AND VEHICLES 

the part of the workman. The grain is obtained by 
dusting the plate with powdered bitumen. 

Besides these there are many other processes, such as 
photo-lithography and photo-zincography which consist of 
the application of photographic methods to lithographic pro- 
cesses. But none of them is of special interest to the artist, 
who is more concerned with process block work than any- 
thing else. 

In conclusion, I may point out that success in black- 
and-white work necessitates the careful study of how each 
effect of the pen or brush will come out in the finished 
reproduction, and until that is learnt the artist cannot 
expect his drawings to be regarded with favour by the 
editors of magazines and others who are experts in the 
matter, no matter how beautiful they may be as drawings. 
Furthermore, the careful study of process work and the 
realisation of its limitations will result, not only in im- 
proved examples of this kind of work, but in the revival 
of the woodcut as the method which gives the feeling 
that can only be produced in work that has the hand 
and not the machine behind it. 



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CHAPTER XVI 

TEMPERA PAINTING 

The conditions of painting have completely altered since 
the time of Van Eycke, and the effects aimed at by modern 
painters, especially those of the Impressionist school, do 
not admit of the same technical processes. Nevertheless, 
some painters still prefer tempera to oil-painting, and it is 
important for those studying the technical processes of 
the art to begin by examining the tempera processes even 
if they do not practise them. There are three things to 
be considered by the artist wishing to produce a permanent 
picture, namely the ground upon which it is painted, the 
pigments used, and the medium with which these pigments 
are prepared. Probably the fifteenth century saw all 
these brought to the greatest perfection compatible with 
permanence, and since then we have obtained new facilities 
in painting at the expense of durability. 

Let us begin by considering the preparation of the 
painting surface for a tempera picture. 

Tempera pictures are painted on wooden panels 
covered with a coat of gesso, and therefore the preparation 
of the panel first claims our attention. The wood usually 
used to-day is mahogany, and it seems to be a trustworthy 



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ioo PROCESSES, PIGMENTS, AND VEHICLES 

material. The wood of the poplar was more commonly 
used in Italy. Small panels can be cut out of one piece 
of wood. This should be thoroughly-seasoned material, 
and the panels are best cut and planed up in the 
spring. 

The panel should not be less than half-an-inch thick, 
and it is a good plan with panels more than nine or ten 
inches in size to cut a couple of undercut grooves in the 
back, across the grain, and let into these two slips of wood. 




SECTION OF PANEL 



These slips of wood must not be glued in, but must be left 
free to expand and contract, otherwise they will split the 
panel. If fitted in in the way described, they will pre- 
serve the panel from warping. 

The panel can be planed up smooth, except on the side 
to receive the gesso. 

This side should be gone over with a toothing plane so 
as to make a surface on which the gesso will firmly 
bite. 

The panels having thus been prepared in the spring 
should be packed away in the carpenter's shop above the 
rafters where they may get plenty of air for twelve months. 
At the end of that time, those which have stood the test 
without warping or cracking may be prepared for painting 
with gesso. 

A very bad custom has grown up of late years of laying 
the gesso directly on the smooth wood. Such a preparation 
is very likely to crack or scale off and cannot be regarded 
as satisfactory. The old Italian method of first pasting 



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TEMPERA PAINTING 101 

over the wood strips of linen is much better, as it holds 
the wood together and makes a good gripping surface 
for the gesso. The linen used should be old, and well 
washed, quite free from size, dressings, and chemicals. 
The glue used should be parchment glue. The method 
of toothing the surface described above is, however, quite 
satisfactory. At this stage of the process' it is as well to 
take the panel to a good picture-frame maker. The gilders 
employed by these men have preserved a tradition of the 
utmost value, and, if proper workmen, may be trusted, 
after direction, to prepare a panel. They are accustomed 
among other things to prepare the parchment glue men- 
tioned above. 

The panel should first be covered with a wash of 
parchment glue well thinned with water. 

Over this the first coat of gesso may be laid. The 
gesso may be prepared either from fine whiting or from 
plaster of Paris, which is fresh, or which has been mixed 
with a large quantity of water, and thoroughly stirred 
at intervals for some weeks. It is then obtained, after 
allowing it to settle and pouring off the water, in a very 
fine state of division, and can be dried and kept for use. 
This preparation seems to have been used in the fifteenth 
century, and is now used by Mr. Watts in preparing 
his canvases. It is, however, troublesome to prepare; 
whiting seems also to have been used with success 
from the earliest times. The prepared plaster of Paris 
or the whiting is mixed with weak parchment glue, and 
spread over the surface, so as to completely cover it, and 
roughly levelled with a spatula, without making it too 
smooth. It should then be allowed to dry for some days, 
and then have a thin coat of the gesso laid over the top 
and carefully smoothed and polished by means of fine glass 



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102 PROCESSES, PIGMENTS^WD VEHICLES 

paper. This, as explained above^B best done by a 
practical picture-frame gilder. ^^ 

After the panel is dry, the artist shwld wash over it 
a thin coat of size, to make it non-abs%bent, and the 
panel is then ready for tempera work. Ifjlhowever, it is 
to be used for an oil-painting, the artist cyi prepare it 
first with a thin priming of such colour as may suit 
him best, mixed with oil, and laid over the gesso. A 
little white lead mixed with oil, and tinted slightly 
according to taste, makes a very good priming for this 
purpose. 

In many cases the old panels underwent a further 
preparation before use, being entirely covered with gold 
leaf, laid on by the process known as water-gilding. There 
can be no doubt that this adds immensely to the durability 
of the work, and it is to be recommended when artists 
can afford the expense. It is, however, important to see 
that the best gold leaf is used, and that water-gilding is 
the process adopted, otherwise the results will not be so 
successful. 

The gold surface is supposed to have a further advan- 
tage, as it is believed to add a peculiar quality to the 
more transparent pigments. This is said to be particularly 
true of flesh-painting, the greenish light thrown off by 
the gold being of great value under flesh tints. 

Having now prepared our painting surface, we can 
proceed to paint on it, in tempera. 

Tempera painting is done either with white of egg or 
yolk of egg. 

If the white of egg is used, it must be thoroughly 
whipped up and allowed to stand for a few hours and the 
clear liquid poured off. The dry colour is then mixed 
with this and ground on a marble slab with a muller. 



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TEMPERA PAINTING 103 

If the yolk of egg is used, the colour can be mixed 
with it and ground on the muller in the same way. It 
used to be the custom, in the fifteenth century, to mix 
with the egg medium a little fig-tree juice. 

This juice contains caoutchouc, and doubtless adds to 
the toughness of the vehicle. Probably, however, the 
best medium is the yolk of the egg, and it may be trusted 
to give very durable results. Many artists at the present 
day mix vinegar or acetic acid with the yolk. This I 
cannot regard as a wise plan unless done with great care. 
There is no evidence of its being used at the best period 
of tempera painting, and the acid is likely to affect many 
pigments which are otherwise permanent. No more acid 
should therefore be added than just sufficient to neutralise 
the alkaline reaction of the egg as tested by litmus paper. 

The difficulties of using this tempera medium are 
sufficiently obvious. The colours have to be fresh ground 
in it pretty frequently, as it does not keep, though by 
adding a little antiseptic it can be made to last for a 
few days, and it does not lend itself to easy manipulation 
with the brush, or to the effects which are now sought for 
in oil-painting. 

Having completed a picture in tempera, it should be 
put on one side for four or five months, and then varnished. 
The best varnishes for this purpose are unfortunately no 
longer available. They were made principally of pine 
balsam, the silver pine for preference, in which a little of 
a harder resin, such as amber, had been dissolved, and a 
very little oil was added, the whole being heated together 
and thinned with turps or naphtha, and then put on warm. 
Four parts of balsam to one of amber and one of oil 
make a good varnish of this kind, and probably Canada 
balsam, which is now imported for mounting microscopic 



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104 PROCESSES, PIGMENTS, AND VEHICLES 

specimens, would do very well. To prepare the varnish, 
pour the Canada balsam, or balsam of the silver pine or 
Venice turpentine, into a hard round-bottomed glass flask, 
and heat over a lamp. Powder the amber, and add slowly 
to the balsam until it is all dissolved, then add the linseed 
oil and heat a little longer until a drop of the varnish 
taken out on the end of a glass rod, and put on a sheet of 
glass, remains quite clear on cooling. Eemove the lamp, 
and cautiously add the turps, shaking the flask after each 
addition, till about as much turps has been added as the 
volume of varnish in the flask. 

If it is too much trouble for the artist to prepare this 
varnish, he must content himself with a copal oil varnish, 
or a mastic varnish, which should be slightly warmed and 
laid over the picture. As the varnish flows over the 
picture all the colours change, and become more trans- 
parent, the final result being similar to an oil-painting. 
In this way 'the most durable pictures were produced in 
the past. If the picture has been painted on gold, and is 
then laid over with a varnish prepared as above described 
(which resists the passage of moisture and injurious gases), 
the result is that the colours are completely protected and 
locked up, and pigments we are accustomed to regard as 
fugitive are permanent under these conditions. 

Sometimes in varnishing certain pigments absorb the 
varnish and dry dead. This is particularly true of terre 
verte. In such cases, a thin wash of size must be painted 
over the pigment before varnishing. 

The palette should be limited, though probably all 
pigments safe in oil-painting may be safely used in 
tempera. 

The picture should not be varnished till at least six 
months from the time of finishing it. 



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TEMPERA PAINTING 105 

The colours ground first to a paste in water can be 
mixed on the palette with the yolk of egg, and the best 
brushes to use are sables. 

This completes the main points that can be given here 
about tempera painting. Manipulation the artist must 
practise for himself. 



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CHAPTER XVII 



FRESCO PAINTING 



True fresco painting or buon fresco is done upon a 
wet ground of lime and sand, only so much of the wall 
being covered with plaster each day as can be painted on. 

Before being plastered, the wall, whether its surface 
be of stone, brick, or mortar, should be thoroughly wetted 
with rain or distilled water. The plaster is applied in 
two or more coats, the coarsest and thickest first. 

The plaster consists of clean sharp white sand well 
washed and lime. There is danger in using the lime on tie 
wall before it is thoroughly slacked, as, if not completely 
slacked, it cracks the plaster. Having slacked the lime 
and mixed it with the sand and sufficient water, it may 
be kept several days before being used. On the other 
hand, if the air is allowed to get at it, the carbonic acid 
in the air combines with it, reconverting it into carbonate 
of lime. 

Now, the setting of the mortar is principally due to 
this slow change, and consequently if it takes place pre- 
maturely it will not set. Professor Church recommends 
running the thick cream of slacked lime into a tank and 
keeping it covered up before using for two months. This 



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FRESCO PAINTING 107 

lime mixed with sand will do for the first layer of plaster. 
For the finer work it should be sifted through hair sieves 
and kept in stoneware jars with air-tight caps. The lime 
may safely contain a certain amount of carbonate, and 
this change takes place to a sufficient extent during the 
time it is in the tank. It is also of considerable import- 
ance that the lime be obtained from a pure carbonate of 
lime, such as a white marble or pure white chalk. 

After the under surface of plaster was dry and before 
laying on the final surface on which the painting was 
done, it was customary during the best period of Italian 
art to draw out completely the design in charcoal, at the 
same time dividing the whole surface into squares, and 
shading the figures in chiaroscuro with the brush. Having 
completed this design, mix the specially-prepared lime with 
very fine sand and lay on a coat \ inch thick, over as 
much surface as you can paint in one day. Before laying 
on this coat, wet the surface thoroughly with rain or 
distilled water. After laying the plaster, wet with a 
large brush and rub over with the wooden tool used by 
plasterers for the purpose. The colours are mixed with 
water and laid on with soft brushes. 

After care in the preparation of the plaster, the next 
thing to remember is that the palette which can be safely 
used in fresco is very limited indeed. 

The earths, whiting, ivory black, charcoal black, 
cobalt blue, and cobalt green, should be the only colours 
used. Most modern frescoes go wrong because the 
palette is unduly extended. The colours are bound in 
position by the setting of the lime, that is, its conversion 
into lime carbonate by the carbonic acid of the air. 

In fresco secco the plaster is allowed to become dry, 
and is then moistened as the painting proceeds with lime- 



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ioS PROCESSES, PIGMENTS, AND VEHICLES 

water, and the pigments mixed with lime-water, and some- 
times a little lime as well, instead of water alone. 

This is an easier process than buon fresco, but is not 
nearly so durable as the other, the paints not being so 
firmly united to the plaster. The lime-water is very 
easily prepared by placing quicklime in water, and pour- 
ing off the clear water, after the lime has settled, into 
bottles carefully corked up to prevent ingress of carbonic 
acid gas. 

Fresco cannot be regarded as a suitable method of 
painting in this country, as the climate is damp, and the 
air in or near our large towns impure. Consequently the 
pigments and ground are attacked by moisture and in- 
jurious sulphur compounds which cause the plaster to 
scale off, and the fresco is darkened by the smoke particles 
in the air. Once coated with these it is very difficult to 
clean the fresco again without injury. 

The old form of fresco painting with lime has been 
largely replaced of late years by * water glass ' or silicate 
of soda processes (stereochromy). 1 

In these processes which have appeared from time to 
time with various modifications and under various names, 
the pigment is mixed with a solution of silicate of soda, 
which combines to form an insoluble compound with the 
lime on the wall and with some pigments. In this way 
the pigment is fixed to the wall surface, and is better 
protected from dirt and moisture than in the case of 
buon fresco. On the other hand, a special and limited 
palette is required for water-glass painting, as the solution 
used destroys certain pigments. 

1 The latest development of stereochromy is known as Eeim's 
Process. Frescoes done by this process can be seen in a chapel at 
Blackheath, Chilworth, Surrey. 



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FKESCO PAINTING 109 

The artist wishing to use one of these processes must 
get the details from those supplying the materials, as they 
would occupy too much space here. 

Its suitability for our damp, smoky climate is, I think, 
open to doubt, and personally, I prefer for this country 
spirit fresco processes as likely to prove more durable, and 
as being more easily cleaned. 

Spirit fresco is really a modified form of oil-painting. 

We owe this process to Monsieur Gambier Parry, though 
the medium used by him was unnecessarily complicated. In 
the first place, before the painting commences, it is essential 
not only that the plaster should be dry, but that the lime 
should have become completely saturated with carbonic 
acid. This can be tested by pressing on the wall, after 
first moistening it, a piece of turmeric paper, which can be 
obtained at any chemist's. If there is still pure lime in 
the plaster, the yellow paper will turn an orange brown. 
If the lime is completely saturated with carbonic acid, the 
paper will not change in colour, and the painting can be 
begun. 

The composition of the different mediums has already 
been given. Professor Church recommends two parts of 
his medium mixed with three parts of turps to prepare 
the ground, and two or three applications of the mixture 
to the ground with a couple of days' interval to let it 
dry. The surface is then ready for priming. This 
should be done with a permanent white, ground in the 
medium. After priming, the surface must be left for 
three weeks before the painting is begun. The pigments 
should be ground in this medium, and turps used to thin 
the paints in laying them on. All pigments which are 
permanent in oil can be safely used. It is important to 
remember that the pigments dry dead, and therefore 



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no PROCESSES, PIGMENTS, AND VEHICLES 

brilliancy is obtained by thin washes as in fresco work. 
Artists have sometimes attempted solid painting with this 
medium, and have naturally been disappointed with the 
results. Some colours, such as the madders, are apt to 
dry a little shiny, even though ground in this medium. 
In such cases, after they are dry, they should be washed 
over with a solution of ozokerite, or white wax in turps. 
A solution of wax in turps is sold as Parry's medium by 
artists' colourmen. It is also necessary to examine care- 
fully whether the more absorbent colours such as the 
earths, and more especially burnt sienna, are firmly fixed 
to the wall, and if not, to touch them lightly over with 
the diluted medium. 

Of course the use of white lead should be avoided 
throughout, especially in decorating buildings in towns, as 
if once darkened it will be impossible to bleach it again. 

Spirit fresco gives great freedom to the artist, a wide 
palette, and durability, with fair protection of the pigments 
against moisture. It is therefore, in my opinion, most 
suited to fresco painting in this country. 

Of the mediums described in the earlier part of the 
work, I have found Church's medium in which the ozokerite 
is replaced by beeswax the most satisfactory, as it fixes 
the colours better, and forms a permanent amalgam with 
the varnish instead of separating from it as the ozokerite 
does. It requires a larger proportion of turps. 



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CHAPTER XVIII 

WATER-COLOUR PAINTING 

Water-colours are prepared for use in three forms, the 
hard cake, the moist cake, and the tube colour. The basis 
in each case is gum water, though the method of prepara- 
tion is varied according to what is required, j 

Besides gum water it is usual to add a little honey 
sugar, which tends to prevent the pigment cracking, and 
where the colour is to remain moist, a little glycerine. 

The sugar used should be that obtained from old honey 
which has been kept some time, the best substance being 
the preparation of lsevulose obtained by treating old honey 
with alcohol and evaporating off the alcohol. The sweet 
substance sold as * Swiss honey' in pots contains large 
quantities of artificially-prepared lsevulose, and will be 
found very suitable for adding to gum water for mixing 
up water-colour pigments. 

Besides honey, a little glycerine may be added to keep 
the colour moist, and when all these are well mixed by 
gently warming and stirring, the colour can be ground in 
the mixture on a muller, and kept in a corked bottle 
ready for use. It will be of the consistency of Chinese 
white as sold in bottles. 



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112 PROCESSES, PIGMENTS, AND VEHICLES 

The following proportions do very well for this pur- 
pose : — 

Gum arabic> 8 parts. 
Water, 30 parts. 
Swiss honey, 5 parts. 
Glycerine, 5 parts. 

Dilute with water, and grind the pigment in this 
mixture. 

The ordinary preparations of water-colours, as supplied 
by artists' colourmen, are quite satisfactory, the main 
question being the selection of a permanent palette. This 
is more difficult in the case of water-colours than in the 
case of oils, because the oil and varnish protect a pigment 
to a certain extent from the action of air, moisture, and 
deleterious gases, while in the case of water-colours the 
pigment is practically left without protection at all. Con- 
sequently, one or two pigments which are used in oil with 
comparative safety must not be used in water-colour. In 
the first place, white lead is replaced by • Chinese white/ 
which is simply a zinc white prepared for water-colour 
work, and quite unchangeable. 

It is as well, also, to exclude purple madder, and the 
use of brown madder is open to doubt, though, personally, 
I do not think it need be excluded. 

With these precautions, the directions for selecting a 
palette for oil-painting will apply to water-colours as well. 

The material on which the painting is done is also 
important. Only the best quality of paper prepared for 
water-colour painting should be used, as commoner papers 
are apt to contain injurious chemicals used for bleaching 
or for adulteration which stain the paper and destroy the 
pigments. The final picture should be mounted so as to 
allow for a free circulation of air between the picture and 



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water-colour PAINTING 113 

the glass, and should not be fastened down on any surface 
such as millboard, or resinous wood which might stain 
the paper. It should be kept as dry as possible, and 
should not be exposed to the direct action of sunlight. A 
little starch paste or pure gum arabic may be used for 
mounting, but made-up cements should be avoided. 



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CHAPTER XIX 

OIL-PAINTING 

Modern pictures are usually executed on canvas, though 
sometimes a panel is used. The preparation of panels 
has been already described. About canvas not much need 
be said. Canvas of good quality is easily obtained, and 
is prepared first by coating with size and then by priming 
with white lead, with which other pigments or other 
materials, such as whiting, may be mixed. In order to 
prevent cracking, a little olive oil is usually mixed with 
the linseed oil. This gives a nice flexible canvas. Some 
artists prefer a canvas merely sized, as they like the 
texture of the cloth to show through the painting, others 
prefer a glue ground. 

There can be no doubt that many of the old canvas 
pictures were painted on gesso, and it has thus proved,* 
capable of standing the test of time ; it has two defects. 
Unless laid on with great skill it is apt to crack off, and 
it is always liable to peel off if the back of the picture is 
exposed to damp air. Mr. Watts, among modern artists, 
always paints on a gesso ground, which he has prepared 
for him with great skill and care. No doubt the result 
will be permanent, if the pictures are carefully guarded 



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OIL-PAINTING 115 

from damp. To a certain extent an oil priming is affected 
by the same danger, the size being softened by damp, and 
so loosening the priming from the canvas. A combination 
of damp, followed by frost, is especially injurious. The 
possible injury in this way from frost seems to have been 
little noticed. And yet many pictures in galleries and 
elsewhere must often be exposed during the night to a 
sufficiently low temperature to freeze any moisture the 
canvas may have absorbed. In this way it is quite easy 
to crack off nearly all the priming from a piece of canvas 
in a few days, by leaving it exposed hanging up out of 
doors during changeable weather. 

It is not usual to protect the back of canvases with a 
priming of paint, but there can be no doubt that this 
would be a useful precaution in all cases whether an oil 
priming or a gesso ground was used for the picture side of 
the canvas. 

Having obtained a suitable piece of canvas, the artist 
proceeds to paint with oil colours already ground for him 
in oil by the artists' colourman. He may use the colour 
directly out of the tube, or he may mix it with some 
vehicle to thin it slightly before use. 

Before considering the different mediums in use it will 
be as well to remind the artist of what he too often 
forgets, that the pigment already contains a large propor- 
tion of oil, and therefore whatever medium he may use 
is merely a mixture of that medium with the oil already 
present. This may seem an elementary fact to point out, 
but nevertheless much confusion of thought is sometimes 
caused by forgetting this. 

The pigment then is delivered to the artist already 
ground in a certain proportion of oil. 

This oil may be linseed oil, or nut oil, or poppy oil, 



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u6 PROCESSES, PIGMENTS, AND VEHICLES 

and the amount present varies with different pigments. 
It is important to note at the outset that we have here a 
medium which only partially protects the pigment from 
gase3 or water vapour, and does not prevent certain 
pigments from acting injuriously on each other. We 
pay for having so delightful a medium to work in by 
at once introducing certain conditions which tend to 
diminish the life of the picture. Not only does the oil 
not exclude moisture or gases perfectly, but it makes it 
impossible to exclude them by means of varnishes, as 
being laid over the elastic oil surface they are bound to 
crack more or less and admit moisture to the interior. 
This is especially true of the varnishes which are moisture- 
tight, and which must contain very little or no oil at all. 

Oil also yellows with age (though it can be bleached in 
the sun), and cracks in a most capricious manner. I 
have made many experiments with different media to try 
and determine causes of cracking, but have failed, because 
none of my experimental canvases will crack. 

Doubtless hasty painting and hasty varnishing are 
mainly responsible for serious cracking, but many cases 
of cracking occur which it is difficult to explain or account 
for. Some conditions not thoroughly understood seem to 
facilitate cracking, causing it to take place in a most 
capricious manner. The trouble is that experiments seem 
to throw no light on the subject, because when we want 
to obtain cracking we cannot get it. Then it is im- 
possible to obtain sufficiently accurate and detailed data 
from artists, to explain such cases as do occur in practice. 
Consequently, beyond the general directions given above, 
very little more can be said at present. 

One most important fact for artists to remember is the 
tendency of whites to get more translucent with time. 



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OIL-PAINTING 117 

This can easily be shown by covering black and white 
squares with white lead until they are completely painted 
out, and then keeping the surface so painted for a year 
or two. Gradually the check pattern appears again 
through the covering of white, showing the tendency of 
the white lead to grow more translucent with time. This 
is of great practical importance to artists, as it shows 
the danger of painting out dark parts of a picture with 
lighter colouring. In fact, in order to keep its brilliancy, 
an oil painting should not, if a section is cut through it at 
any point, pass from lighter to darker pigments downwards, 
but should pass always from darker to lighter pigments. 
For the same reason, a white ground probably does a good 
deal to preserve the permanent brilliancy of a picture. 

It is also of importance to avoid an excess of oil or 
medium in painting. Mr. Watts, who is one of our most 
careful painters, always has his colours ground specially 
stiff, and avoids the use of additional oil. This leads 
naturally to the question of the use of mediums. 

Raw or boiled oil, copal oil varnish, amber oil varnish, 
turpentine, and petroleum, may all be safely used, or the 
artist may mix them together to suit his taste. A little 
copal or amber varnish is useful, as it hardens the surface 
of the picture, oil alone being rather soft. Turpentine 
has the fault of not evaporating clean, but leaving some 
resin behind. This fault varies with different varieties 
of turps. Petroleum properly rectified is the cleanest of 
all mediums, as it evaporates completely and leaves no ' 
residue. Probably copal oil varnish thinned with petroleum 
is as safe and useful a medium as an artist can use. 

For sketching it is sometimes useful to have the medium 
in the form of a jelly. This can be done by the addition 
of a little beeswax to oil or varnish. All patent mediums, 



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Ii8 PROCESSES, PIGMENTS, AND VEHICLES 

all patent dryers, all dryers containing lead compounds, 
such as sugar of lead, and boiled oils and varnishes 
containing lead compounds, should be avoided. 

Any oil, varnish, dryer, or medium, which on mixing 
with a little glycerine and a few drops of sulphide of 
ammonium turns dark brown, contains some lead compound 
and should be avoided. 

Boiled oils and varnishes are now prepared with 
• manganese instead of lead, and should always be used. 
A picture before varnishing should be gently washed, then 
put in a warm place to dry thoroughly. Mastic should 
be used and the varnish should be slightly warmed, and 
the picture finally rubbed with a warm dry cloth before 
the varnish is laid on. The picture should be kept before 
varnishing until it is at least six months old. The advan- 
tage of mastic over oil varnishes is that it is easily removed 
without injuring the picture, when cleaning is necessary. 

In conclusion, I may refer artists wishing to study these 
subjects in more detail to Professor Church's work on 
Paints and Painting, which is full of most valuable infor- 
mation. 



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GLOSSARY OF PIGMENTS 

(P for Permanent, F for Fugitive.) 



Name. 


O 


PS 

5§ 


o i 


Remarks. 




fc 


£ 






Alizarine Lakes . 


P 


P 


F 


These lakes are made from 
the dyeing principle of the 
madder root. 










Antwerp Blue . 


P 


P 


F 


A variety of Prussian blue. 


Artificial Ultramarine 


P 


P 


F 




Asphaltum 


P 


P 


F 


Bitumen. 


Asphalt Brown . 


F 


F 


F 


A variety of asphaltum. 


Aureoline . 


P 


P 


F 


Cobalt yellow. 


Aurora Yellow . 


P 


P 


F 


A pale cadmium, specially 
prepared. See chapter on 
Artificial Yellows. 


Azure Blue 


P 


P 


P 


A variety of cobalt blue. 


Baryta White 


P 


P 


P 


Sometimes called permanent 
white. 


Baryta Yellow . 
Berlin Blue 


P 


P 


F 


Lemon yellow. 


P 


P 


F 


A variety of Prussian blue. 


Bitumen 


P 


P 


F 


A dangerous pigment. See 
chapter on Bitumens. 










Blanc de Argent . 


P 


F 


F 


A fine variety of white lead. 


Blanc de Plomb . 


P 


F 


F 


White lead. Turns brown 
in impure air. See chap- 
ter on Whites. 


Blanc de Zinc . 


P 


P 


P 


Zinc white. 


Blanc Fixe . 


P 


P 


P 


Baryta white. 


Blacklead . 


P 


P 


P 




Bleu de Berlin . 


P 


P 


F 


A variety of Prussian blue. 


Bleu de Thenard 


P 


P 


P 


A cobalt blue. 



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120 



PROCESSES, PIGMENTS, AND VEHICLES 



Name. 



Blue Celeste 
Blue Black 
Bone Black 
Bone Brown 
Brown Madder 
Brown Red . 
Brun Rouge 
Burnt Sienna 
Burnt Umber 
Burnt Ochre 
Cadmium Gelb 

Cadmium Yellow 



Caelin 
Caelin Blau 
Caledonian Brown 
Cambridge White 
Cappagh Brown . 
Carmine 

Carmine de Garance 
Cassel Earth 

Caeruleum . 
Cerulean Blue . 
Cerulian 
Ceruse 

Chape'oal Black . 
Cinnabar Green . 



Chinese Blue 
Chinese White 
Chrome Greens 
Chrome Red 
Chrome Yellow 
Cobalt Blue 
Colcothar . 
Cologne Earth 
Crimson Lake 
Crocus 
Cyanine Blue 



J 

? 

'A 


OS 


P 


p 


P 


p 


P 


p 


F 


F 


P 


F 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


P 


F 


F 


P 


P 


F 


F 


P 


P 


P 


P 


P 


P 


P 


F 


P 


P 


F 


F 


P 


P 


P 


P 


F 


F 


F 


F 


F 


F 


P 


P 


i P 


P 


F 


F 


F 


F 


P 


P 


P 

I 


P 



&4 



Remarks. 



A variety of cobalt blue. 


A charcoal black. 


A red ochre. 


A red ochre. 


See chapter on Artificial 


Yellows. 


See chapter on Artificial 


Yellows. 


A variety of cobalt blue. 


A variety of cobalt blue. 


A brown earth. 


See chapter on Whites. 


A variety of umber. 


A cochineal lake. 


A madder lake. 


See chapter on Bituminous 


Earths. 


A variety of cobalt blue. 


A variety of cobalt blue. 


A variety of cobalt blue. 


White lead. 


Usually a mixture of chrome 


yellow and Prussian blue. 


Sometimes oxide of chro- 


mium, then permanent. 


A variety of Prussian blue. 


Zinc white. 



Red ochre. 

See Bituminous Brown. 
A cochineal lake. 
Red ochre. 

Cobalt blue and Prussian 
blue. 



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GLOSSARY OF PIGMENTS 



Name. 


o 


*5 


*8 


Remarks. 




fc 


► 


"fa 


_ i 


1 Daffodil . 

i 


. P 


P 


F 


A permanent pale cadmium 
yellow. See chapter on- 
Artificial Yellows. 


Emerald Green 


. P 


P 


F 


Must not be mixed with cad- 
mium yellow. 


i Emerald Oxide of 


Chro- 








mium 


. P 


P 


P 




Flake White 


. P 


F 


F 


White lead. Sec chapter on 
Whites. 


Foundation Whii 


be . P 


F 


F 


White lead. 


Freeman's White 


. P 


P 


P 




I French Blue 


. P 


P 


F 


Ultramarine. 


Gamboge . 


. F 


F 


F 




i Geranium Lake 


. F 


F 


F 




Gelben Ocker 


• P 


P 


P 




Gmelin's Blue 


. I P 


P 


F 


Ultramarine. 


Golden Ochre 


. I P 


P 


P 




I Graphite . 


. ' P 


P 


P 




Green Bice . 


• I P 


F 


F 


Malachite green. 


Green Lake 


. F 


F 


F 




Green Verditer 


. P 


F 


F 


Malachite green. 


Grune Erde 


. P 


P 


P 


Terre Verte. 


Grune Chrome 


. F 


F 


F 




Guimet's Blue 


. P 


P 


F 


Ultramarine. 


Hooker's Green 


. F 


F 


F 




Indigo 


. F 


F 


F 




Indian Purple 
Indian Yellow 


. P 


P 


P 


A purple ochre. 


. F 


F 


F 




Indian Lake 


. F 


F 


F 




Indian Red 


. P 


P 


P 


A red ochre. 


Italian Pink 


. ' F 


F 


F 




j Ivory Black 


. P 


P 


P 




Jaune de Chrome 


3 . F 


F 


F 




Jaune Brilliant 


. P 


P 


F 


A cadmium yellow. See 
chapter on Artificial Yel- 
low. 


Jaune de Cobalt 


. P 


P 


F 


King's Yellow 


. ; F 


F 


F 


Orpiment. 


| Kobalt Gelbe 


. P 


P 


F 




Kobalt Blau 


. P 


P 


P 




Krapp Lac 


. P 


P 


F 


Madder lake. 


' Kremzer Weiss 


. P 

I 


F 


F 


White lead. See chapter on 
Whites. 


Lamp Black 


• ! p 


P 


P 




Laque de Garanc 


e . P 


P 


F 


Madder lake. 

1 



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PROCESSES, PIGMENTS, AND VEHICLES 



Name. 


o 


05 

•5 5 


if 


REMARK8. 




* 


£ 


CO 05 




Laque Robert 


. F 


F 


F 




Lemon Yellow 


. P 


P 


F 




Light Red . 


. P 


P 


P 


Red ochre. 


Madder Lake 


. P 


P 


F 




Magenta 
Malachite Green 


. F 


F 


F 




. P 


F 


F 




Mars Brown 


. P 


P 


P 


An artificial brown ochre. 


Mars Orange 


. P 


P 


P 


An artificial brown ochre. 


Mars Red . 


. P 


P 


P 


An artificial red ochre. 


Mars Violet 


. P 


P 


P 


An artificial purple ochre. 
An artificial yellow ochre. 


Mars Yellow 


. P 


P 


P 


Mauve 


. F 


F 


F 




Miller's Green 


. P 


P 


P 


Oxide of chromium. 


Mineral Green 


. P 


F 


F 


Malachite green. 


Mineral Yellow 










Mummy 


'. P 


F 


F 




Mutrie Yellow 


. P 


P 


F 


A cadmium yellow. See 
chapter on Artificial 
Yellow. 










Naples Yellow 


. P 


F 


F 




New Blue . 


. P 


P 


F 


Ultramarine. 


New Flake Whit 


e . P 


P 


P 


See chapter on Whites. 


Ocre Jaune . 


. P 


P 


P 




Olive Lake . 


. F 


F 


F 




Orient Yellow 


. P 


P 


F 


A cadmium yellow. See 
chapter on Artificial 
Yellow. 










Orpiment . 


. F 


F 


F 




Oxford Ochre 


. P 


P 


P 




Oxide of Chromii 


xm . P 


P 


P 




Palladium Red 


. F 


F 


F 




Palladium Scarle 


t . F 


F 


F 




Pariser Blau 


. P 


F 


F 


A Prussian blue. 


Patent Yellow 


. F 


F 


F 




Permanent Blau 


. P 


P 


F 


Ultramarine. 


Permanent Whit 


e . P 


P 


P 


Baryta white. 


Permanent Weis 


3 . P 


P 


P 




Persian Red 


. F 


F 


F 




Pink Madder 


. P 


P 


F 




Platina Yellow 


. F 


F 


F 




Plumbago . 


. P 


P 


P 




Prussian Blue 


. P 


F 


F 




Prussian Green 


. F 


F 


F 




Pure Scarlet 


. F 


F 


F 




Purple Lake 


. F 

1 


F 


F 





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GLOSSARY OF PIGMENTS 



123 



Name. 







4 


Remarks. 




S5 


A 


«£ 




Raw Sienna 


P 


p 


P 




Raw Umber 


P 


p 


P 




Red Lead . 


F 


F 


F 




Red Ochre . 


P 


P 


P 




Rembrandt's Madder . 


P 


P 


F 




Rinmann's Green 


P 


P 


P 


A cobalt green. 


Roman Ochre 


P 


P 


P 




Rouge 


P 


P 


P 


A red ochre. 


Rouge Anglais . 
Rose Madder 


P 


P 


P 


A red ochre. 


P 


P 


F 




Rubens' Madder . 


P 


P 


F 




Ruby Madder 


P 


P 


F 




Sap Green . 


F 


F 


F 




Saxon Blue 


P 


P 


F 


A Prussian blue. 


Scarlet Chrome . 


F 


F 


F 




Scarlet Lake 


F 


F 


F 




Scheele's Green . 


P 


P 


F 


A variety of emerald green. 


Schweinfurt Green 


P 


P 


F 


A variety of emerald green. 


Sepia .... 


P 


P 


F 




Silver White 


P 


F 


F 


A white lead. See chapter 
on Whites. 


Smalt 


F 


F 


F 




Terra de Verone . 


P 


P 


P 


Terre verte. 


Terre Verde 


P 


P 


P 




Terre Verte 


P 


P 


P 




Terra Rosa , 


P 


P 


P 


A red ochre. 


Turnbull's Blue . 


P 


F 


F 


A variety of Prussian blue. 


Turner's Yellow . 


F 


F 


F 




Ultramarine 


P 


P 


F 




Ultramarine Ash 


P 


P 


F 




Vandyke Brown . 


F 


F 


F 


See Bituminous Earths. 


Venetian Red 


P 


P 


P 




Verdigris . 
Vermilion . 


F 
P 


F 
P 


F 
F 




Verona Brown . 


P 


P 


P 


A variety of umber. 


Veronese . 


P 


P 


F 


Emerald green. Do not mix 
with cadmium yellows. 


Vert de Cobalt . 


P 


P 


P 




Vert de Chrome . 


P 


P 


P 


An oxide of chromium. 


Vert de Guignet . 


P 


P 


P 


An oxide of chromium. 


Vert de Montagne 


P 


F 


F 


A malachite green. 


Vert de Zinc 


P 


P 


P 


A cobalt green. 


Vert Emeraude . 


P 


P 


P 


Viridian. 


Vert Paul . 


P 


P 


F 


An emerald green. 


Violet Carmine . 


F 


F 


F 





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124 



PROCESSES, PIGMENTS, AND VEHICLES 



Name. 


o 


In 

Water. 

Buon 
Fresco. 


Remarks. 

An oxide of chromium. 
See chapter on Whites. 

Not a madder lake. 

A lemon yellow. 


Virgin Gold Ochre 

Viridian 

White Lead 

Yellow Carmine . 

Yellow Madder . 

Yellow Ochre 

Yellow Ultramarine . 


i P 

1 p 

1 F 

1 F 

P 

P 


'pip 
p p 

F F 

F 1 F 
F F 
P P 
P F 

1 



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INDEX 



Air, composition of, 30 
Alizarine, 55 
Aloes, 71 
Alumina, 67, 55 
Alum, 55 
Amber, 70 
Amber Varnish, 73 
Asphaltum, 36 
Aureoline, 52 
Aurora Yellow, 52 

Balsam, Canada, 71 
Barium Chromate, 50 
Barytes, 46 
Beeswax, 75 

Bitumen, preparation of, 37 
„ of Judea, 36 
„ dangers of, 37 
Blue, Prussian, 57 

„ Cobalt, 57 
Black, Bone, 63 

„ Ivory, 63 

„ Lamp, 63 

„ Vine, 63 
Blue, Cerulean, 58 
Boiled Oil, 67 
Bone Black, 63 
Borate of Manganese, 67 
Brown Madder, 56 

„ Ochre, 27 
Buon Fresco, 106, 107 
Burnt Sienna, 27, 29 

Cadmium Yellow, 51 
Cambridge White, 49 
Canada Balsam, 71 



Canvas, 114 
Cappagh Brown, 35 
Carbonic Acid Gas, 40 
Carbonates, 42 
Carmine, 56 
Cassel Earth, 38 
Cerulean Blue, 58 
Chinese Vermilion, 54 

„ White, 48 
Chrome Yellow, 50 

„ Greens, 51 

„ Orange, 51 
Church's Medium, 75 
Cobalt Blue, 57 

„ Green, 61 

„ Yellow, 52 
Cochineal, 56 
Collotype, 95 
Cologne Earth, 38 
Coloured Varnish, 74 
Copal, 70 
Copal Varnish, 72 
Copperas, 39 
Crimson Lake, 56 
Cyprus Umber, 34 

Daffodil, 52 
Dragon's Blood, 71 
Dryers, Umber, 34 
Drying Oils, 67, 68 
Dutch Pink, 53 

Egg Medium, 102 
Emerald Green, 61 

Flake White, 42, 43, 44 



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126 



PROCESSES, PIGMENTS, AND VEHICLES 



Freeman's White, 49 
Fresco Secco, 107, 108 
Fresco, Buon, 106, 107 

Gamboge, 53, 71 
Gambier Parry Medium, 75 
Gesso, 101 

Glue, Parchment, 101 
Golden Ochre, 22 
Green Emerald, 61 

„ Cobalt, 61 

„ Malachite, 30 

„ Oxide of Chromium, 60 

„ Vitriol, 28 
Grounds, 114 
Gum Arabic, 113 

Half-tonb Process Block, 90, 91 

Indian Red, 27 

,, Yellow, 53 
Indigo, 59 
Iron, test for, 23 
Italian Pink, 53 
Ivory Black, 63 

IxfiVULOSE, 111 

Lake, Crimson, 56 

„ Madder, 55 

„ Purple, 56 

„ Scarlet, 56 
Lamp Black, 63 
Lapis Lazuli, 39 
Lead Acetate, 42 

„ Carbonate, 42 

„ Chromate, 51 
Lemon Yellow, 50 
Light, exposure to, 16 
Light Red, 27 
Lime for Fresco, 106 
Linseed Oil, 65, 66 

Madder Brown, 56 

,, Lake, 56 

,, Purple, 56 
Malachite Green, 39 
Manganese, 33 

„ Borate of, 67 

Marble White, 49 * 
Mars Purple, 27 



Mars Red, 27 
Mastic, 70 

„ Varnish, 73 
Mediums, 117 

Medium, Gambier Parry, 75 
Mercury, Sulphide of, 54 
Muller, 13 

Naples Yellow, 52 
New Flake White, 49 
Nut Oil, 65 



Ochre, Adulteration of, 25 
„ Red, 27 
„ Brown, 27 
„ Purple, 27 
,, Roasting of, 27 
„ Yellow, 22 
,, Golden, 22 
„ Oxford, 22 
,, Roman, 22 
Oil, Boiled, 67 
Drying, 67, 68 
Linseed, 65, 66 
Nut, 65 
Poppy, 65 
Spike, 76 
Varnish, 71 
Oleo de Abezzo, 71 
Orange Chrome, 51 
Oxford Ochre, 22 
Oxides, 30 

Oxide of Chromium, 60 
Oxygen, 30 

Panels, 99, 100 
Paraffin Wax, 75 
Parry Medium, 75 
Peroxide of Hydrogen, 46 
Petroleum, 76 
Photogravure, 97 
Pigments for Fresco, 107 
Plaster of Paris, 101 
Poppy Oil, 65 
Process Block, 84, 85 
Prussian Blue, 57 
Purple Lake, 56 

,, Madder, 55 

,, Ochre, 27 

„ Oxide, 27 



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INDEX 



127 



Raw Sienna, 22, 25 
Red Ochre, 27 

„ Ochre from Green Vitriol, 

„ Oxide, 27 
Roman Ochre, 22 
Rouge, 27 
Rust, 30 

Sandarac, 70 
Scarlet Lake, 56 
Shellac Varnish, 74 
Spike, Oil of, 76 
Spirit Varnish, 71 

„ Fresco, 109, 110 
Stereochromy, 108 
Stippling, 87 
Sugar of Lead, 42 
Sulphate of Iron, 28 
,, Lead, 48 

,, Zinc, 68 

Sulphide of Mercury, 54 
Swiss Honey, 111 

Terrb Verte, 29 
Turpentine, Oil of, 76 

,, Varnish, 71 

,, Venice, 71 

Ultramarine, 58 

„ Real, 39 

Umber, 33 



28 



Vandyke Brown, 38 
Varnishing, 118 
Varnish, Copal, 72 

„ Mastic, 73 

,, Shellac, 74 

,, Coloured, 74 

,, Spirit, 71, 72 

,, Turpentine, 71, 72 

„ Oil, 71, 72 

,, in Tempera, 104 
Venetian Red, 27 
Venice Turpentine, 70 
Vermilion, 54 
Vine Black, 63 
Viridian, 60 

Wax, 75 
White, 42, 43, 44 

White Lead, action of Sulphur Gas 
on, 45 

Yellow Aurora, 52 
,, Cadmium, 51 
,, Chrome, 50 

Cobalt, 52 
,, Indian, 53 
,, Lemon, 50 
,, Naples, 52 
,, Ochre, 22 

Zinc, Sulphate of, 68 
„ White, 47 



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LIST OF APPARATUS AND CHEMICALS 
REQUIRED 



1 oz. Chlorate of Potash 








£0 3 


1 oz. Iron Filings . 








2 


1 oz. Salamoniac 








2 


1 oz. Black Oxide of Manganese 








2 


1 oz. Gum Arabic . 








3 


1 oz. Asphaltum 
1 oz. Cobalt Nitrate 








2 








9 


1 oz. Ammonia 








4 


1 oz. Strong Sulphuric Acid 
1 oz. Nitric Acid 








4 








4 


1 oz. Hydrochloric Acid 








4 


1 oz. Ammonium Sulphide . 








4 


1 oz. Sulphate of Iron 








4 


1 oz. Lead Acetate . 








2 


1 oz. Sodium Sulphate 








3 


1 oz. Sodium Hyposulphite 
1 oz. Acetic Acid 








2 
4 


1 oz. Barium Chloride 








2 


1 oz. Potassium Chromate . 








3 


1 oz. ,, Bichromate 








3 


1 oz. Cadmium Sulphate 








7 


1 oz. Alum . 








2 


1 oz. Sulphate of Copper 








2 


1 oz. Potassium Ferrocyanide 








4 


1 oz. Boracic Acid . 








2 


1 oz. Gypsum 
1 oz. Soda . 








2 
1 


1 oz. Barytes 








6 


1 oz. Alizarine 








10 


1 oz. Alumina 








4 


1 oz. Spirits of Wine 








2 


Pieces of Marble 








3 


Thin Iron Wire 








3 



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ISO 



PROCESSES, PIGMENTS, AND VEHICLES 



Stout Copper Wire . 

Bitumen 

Mortar and Pestle . 

1 doz. Test-tubes 
Small Test-tube Stand 
Nest of 6 Beakers . 
Crucible Tongs 
Platinum Fofl2"xl" 

2 Spirit Lamps 
Mouth Blowpipe 
Stoneware Tray 
Gas Jar 

Packet of Filter Papers 
2 Glass Funnels 
Funnel Stand 
Bottle with Tube, Cork, and Thistle Funnel 
2 Round-bottom Hard Glass Flasks 
Stoppered Bottle, 4 oz. 
2 Small Spatulas 

2 Iron Tripods 

Box for holding 1 doz. J Plates 
Muller and Slab 

3 Porcelain Plates . 
Frame with Sheet of Glass in it 

1 doz. Glass Plates twice the size of J Plates 
Frame for Exposing Glass Plates 
Glass Plate, 5 sq. . 
Small Sheet Iron Dish • 
Small Iron Ladle 

2 Wide-mouthed Bottles, 8 oz. 
1 oz. Cochineal 
1 oz. Linseed 
1 oz. Crimson Lake . 
1 oz. Madder ,, 
1 oz. Alizarine ,, 
1 oz. ,, „ . 
1 oz. Carmine 
1 oz. Oxide of Chromium 
1 oz. Cobalt Green . 
1 oz. Cobalt Blue . 
1 oz. Chinese Vermilion 
1 oz. Cadmium Orange 
1 oz. Daffodil No. 1 
1 oz. „ No. 2 
1 oz. Cobalt Yellow . 
1 oz. Cyprus Umber 
1 oz. Raw Sienna . 
1 oz. Golden Ochre . 
1 oz. Oxford Ochre . 
1 oz. Virgin Gold Ochre 
1 oz. Chrome Yellow 



£0 





















































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APPARATUS AND CHEMICALS REQUIRED 131 



1 oz. Red Ochre 








£0 6 


1 oz. Purple Ochre . 








6 


1 oz. Burnt Sienna . 








6 


1 oz. Terre Verte 








6 


1 oz. Raw Umber 








6 


1 oz. Burnt Umber . 








6 


1 oz. Cappagh Brown 
1 oz. Vandyke Brown 








6 
6 


1 oz. White Lead 








6 


1 oz. Best Flake White 








6 


1 oz. Freeman's White 








6 


1 oz. Zinc White 








6 


1 oz. ,, ,, (Condensed) 








6 


1 oz. Naples Yellow 








6 


1 oz. English Vermilion 








6 


1 oz. Prussian Blue . 








6 


1 oz. Emerald Green 








6 


1 oz. Chrome Green . 








6 


1 oz. Ivory Black . 
1 oz. Verdigris 








6 








10 


1 oz. Lamp Black . 








10 


1 oz. Vine Black 








10 


1 oz. Ultramarine . 








10 


1 oz. Cerulean Blue 








16 


1 oz. Indigo . 








2 


Tube of Yellow Ochre 








4 


1 oz. Poppy Oil 








3 


1 oz. Linseed Oil 








3 


1 oz. Turps . 








3 


1 oz. Petroleum 








3 


1 oz. Whiting 








1 


Varnished and Dovetailed Box with Lock 




12 




£6 16 4 



THE END 



Printed by R. & R. Clark, Limited, Edinburgh 



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THE CAMBRIDGE COLOURS. 

A SELECTED PALETTE OF TESTED PIGMENTS. 



ALL THE PIGMENTS INCLUDED IN THIS PALETTE 
MAY BE SAFELY MIXED TOGETHER WITHOUT DANGER 
OF THEIR ACTING INJURIOUSLY ON EACH OTHER. 

THE ONLY SCIENTIFIC PALETTE, 



Testimonials from many Leading Artists, including 
Sir E. Burne-Jones, Bart. 

Sir J. E. Millais, Bart. 

Sir Fred. Leighton, Bart. 

" May 27, 1892. 
" 2 Holland Park Road, 
" Messrs. Madderton & Co., " Kensington, W. 

"Gentlemen — I have to thank you for some specimens of your 'Cambridge 
Colours ' which you have been good enough to send me. I may say that those colours 
are already favourably known to me as being fine in tone and well ground. I find 
great use, for instance, in your Daffodil Yellow and Yellow Cobalt. Your Ruby 
Madder also is of a very fine hue. 

" I am, Gentlemen, 

"Yours faithfully, 

"Fred. Leighton, P. R. A." 



THE NEW FLAKE WHITE. 

This White combines the good qualities of the very best Flake White 
in the market with the inestimable advantages of being 

PRACTICALLY NON-POISONOUS, 

and consequently not causing Painters' Colic, or Paralysis of the 
Hand, and of 

RETAINING ITS COLOUR IN IMPURE AIR. 

The only lead compound it contains is lead sulphate, which is prac- 
tically harmless and unchangeable, whereas ordinary Flake White con- 
sists of the deadly and easily-discoloured Lead Carbonate. 

This White is being used by the Birmingham Municipal Art School to 
paint the panels for the Town Hall, some of which have been exhibited at 
the Arts and Crafts Exhibition. 



All Colours through any Artists' Colourman, or sent direct 
from Loughton. 

MADDERTON & CO., Loughton, Essex. 

WHOLESALE AGENTS FOR THE TRADE: 

C. F. MABBT & CO., Ld., 4 Golden Lane, London, E.C. 

General Dealers in Artists Materials. 



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NOV 2 2 1938 




y Google 



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